You are here:

Algebra/Questions Answered by Expert Abe Mantell

Subject	Date Asked
word problems	1/17/2012
Q: if 17 girls can plant 51 trees in a day. how many trees could 26 girls plant in an hour? A: 17 girls planting 51 trees in one day ==> 1 girl can plant 51/17 = 3 trees per day. Now divide that ...
Algebra I/Elimination using Multiplication	1/10/2012
Q: I'm stumped on a word problem with elimination using multiplication. It's adding in percents and ... A: This can be done with only one variable, but since you mentioned elmination, I gather you need to ...
Quadratics	1/6/2012
Q: I've got a test for quadratics in a few days, and I don't understand the homework we are doing ... A: The equation governing the motion of an object subject to acceleration is: y(t)=(1/2)at^2+vot+yo, ...
Algebra woes.	1/5/2012
Q: 1.) List the possible rational roots of the following equation: 5x4 + 9x3 + 5x2 + 2x + 4 = 0 ... A: The rational root theorem tells us that the possible rational roots of a polynomial with integer ...
Pi	12/31/2011
Q: I don't know if you're the right person to ask but please could you help with this or let me know ... A: I think you mean "is pi still irrational (not perfect) if expressed in another base"...yes? A ...
Algebra!	8/18/2011
Q: I reallllyyy need help with this please!! It's Fractional Equations... ... A: 18. k/(k+1) + k/(k-2) = 2 We can get a common denominator, (k+1)(k-2), or justy multiply both sides ...
trinomials	8/17/2011
Q: how do you multiply 2 trinomials together? A: One way is as follows: First you take the first term of the first trinomial and distribute it to the ...
Re: Help!	8/16/2011
Q: elimination method: after you multiply first equation to get one of the variable alike to the second ... A: If the two equations turn out to be the same (after multiply or dividing by the appropriate ...
Calculus	8/13/2011
Q: I feel like i am missing information to solve this problem. It is a surprising biological fact that ... A: If we let x=the number of chirps in 15 seconds, then the temperature is approximated by: T(x)=x+40, ...
Invention of the Wheel - Circular Shape	8/12/2011
Q: Invention of the Wheel ---------------------- There are Two Wheelers, Three Wheelers and Four ... A: My opinion about using non-circular wheels? I think circular wheels are the best all-purpose wheel ...
Invention of the Wheel - Circular Shape	8/11/2011
Q: Invention of the Wheel ---------------------- There are Two Wheelers, Three Wheelers and Four ... A: My response is pretty much the same as before. For flat roads, circular tires are best. We can ...
algebra equation	8/1/2011
Q: My maths is not terrific and I'm having a bit of trouble understanding how an equation that has ... A: The equation is best written: (2x)^2/((1.000 - x)(2.000 - x)) = 50.5 now multiply both sides by ...
Polynomial	7/27/2011
Q: Could you please explain how to determine if a polynomial is the difference between two squares? I ... A: The difference of two squares is of the form: x^2 - y^2, which factors to (x-y)(x+y) For example: ...
Negative Exponents	7/25/2011
Q: To simplify an equation such as: (X^-2+3)/(X-2) Do you actually have to multiply both sides of the ... A: (X^-2+3)/(X-2) is not an equation, it is an algebraic expression (an equation has an "equals" sign ...
Basic algebra	7/16/2011
Q: A new cruise ship line has just launched 3 new ships: the Pacific Paradise, The caribbean paradise, ... A: Let c=the number of deluxe rooms on the Caribbean Paradise, p=the number of deluxe rooms on the ...
Algebra 1 9th Grade	7/8/2011
Q: I do not understand the Elimination method. Please help me, Can you go step by step? x-2y=12 ... A: The elimination method involves adding or subtractin multiples of the equations so that one of the ...
Quadratic equations and graphing quadratic equations	7/2/2011
Q: "I am having difficulty with a few problems in my college algebra class. Thank you so much for your ... A: Sorry for my delay, I was away for a few days and forgot to set "vacation" mode... 1. (x-2)^2=20 ...
Radical Expressions and Radical Equations	6/17/2011
Q: This is my second semester of Algebra in college and need help on a few problems. 1. Multiply. i ... A: 1. How do you get a negative result? The product of two positive numbers is positive. . ...
math	6/6/2011
Q: what is the square root of 5,-8,13,-16,-0.7,4.3 A: Do you want the square root of each of the 6 numbers seperately? If so, then here you go (to 10 ...
algebra	6/5/2011
Q: how do you solve and graph 5x<2x+15 ? A: You solve inequalities just like equalities, except when multiplying or dividing by a negative ...
Trignometry	6/4/2011
Q: The volume of air in the lungs of a certain long distance runner is modelled by the eqauation ... A: 1. V_minimum occurs when the sine function is a minimum, which is -1 (the sine function . goes from ...
Vectors and Coordinates	5/26/2011
Q: 1)The magnitude and direction of vectors u and v are given. Find vector w's polar coordinates. u: ... A: 1. In rectangular coordinates: u=(136cos(220°),136sin(220°)) = (-104.182,-87.419) ...
Math	5/24/2011
Q: Algebra 1 I need help on solving this problem 7/5x-3/6= -258/30x A: I will assume the equation is: (7/5)x-3/6=(-258/30)x ...OK? In that case, first add (258/30)x to ...
Annual Percentage Yield Calculation	1/7/2011
Q: I'm not sure whether or not this is a basic math or algebra category question; so I posted it here. ... A: Actually, the APY is (1 + r/n)^n-1 For example... Suppose an APR of 4% compounded monthly, so r=0.04 ...
algebra	1/6/2011
Q: in 1995 the life expectency of males in certain country was 73.1 in 2002 it was 76.3 years, let E ... A: There are many models we could use...linear, exponential, logarithmic, etc. In order to know which ...
Algebra II	1/5/2011
Q: What is x squared-1 is greater than or equal to 0? A: x^2 - 1 >= 0, factor the left hand side (x+1)(x-1) >= 0, The only way the product of two numbers ...
Algebra	12/29/2010
Q: Where e = the number e F = 5e^-.04h can be used to find the number of milligrams F of a certain ... A: What is your 3rd step: -.04h = log5e of 2 ??? It should be: ln(2)=ln(5e^-0.4h) and then: ...
linear equation	9/2/2010
Q: I have a straight line linear equation, I think it's a bit crazy, but here it is: -0.004 = 0.001x ... A: The x-intercept corresponds to y=0. So, just let y=0 then solve for x. The problem here is that ...
Quick Question	8/31/2010
Q: I am trying to help my daughter with her math homework and I am rusty. She needs to simplify ... A: m+m=2m, because m can be represented as 1m so 1m + 1m is (1+1)m=2m, i.e. we just add the ...
Future Value & Compound Interest	8/30/2010
Q: If the principal earns compound interest for 4 years. expanded calculation is as follows: P(P ... A: At the end of: 1st half year: P (r/2)P 2nd half year (or 1 yr): P (r/2)P (r/2)[P (r/2)P] 3rd half ...
help with math	8/28/2010
Q: I was doing a HW problem (for my electronics class) and it comes down that I have the following ... A: Let me rewrite your equation: 10[R/(1000 + R)] - 10[1500 + R] = 1 Now getting rid of the brackets: ...
algebra 2	8/27/2010
Q: Use the Rational Roots Theorem to solve for the rational roots 3x4 - 2x3 + 8x2 - 6x - 3 = 0 A: I gather you meant: 3x^4 - 2x^3 + 8x^2 - 6x - 3 = 0 So, the rational root theorem states that if ...
Algebra 2	8/26/2010
Q: write equations of the lines through the point (a) parallel to the given line and (b) perpendicular ... A: Since you are given a point (3,-2), now all you need is a slope. 1. Parallel to 5x-4y=8, means that ...
Compound Interest	8/25/2010
Q: I have a question regarding the following compound interest and future value calculation. Year 1, ... A: Brackets are OK, but not necessary where you placed them, the parentheses already group the same ...
Compound Interest	8/23/2010
Q: I have a question regarding the following compound interest and future value calculation. Year 1, ... A: End of 4th year: (P+rP)+r(P+rP)+r[(P+rP)+r(P+rP)]+r[(P+rP)+r(P+rP)+r[(P+rP)+r(P+rP)]] =P(1+r)^4 End ...
Compound Interest	8/22/2010
Q: I have a question regarding the following compound interest and future value calculation. Year 1, ... A: The following year it will be previous amount plus r times the previous amount. So, the 3rd year ...
Integrals	8/21/2010
Q: I am battling to study due to a rare eye problem. Please can you show me how to solve these ... A: a) ∫√(9 – x^2) dx, make the substitution x=3sin(u) ==> x^2=9sin^2(u) and dx=3cos(u) du, ...
Exponents	8/20/2010
Q: I was wondering if you could help me solve for x in this equation: 4^x+4^(-x)= 5/2 I've tried to ... A: The equation can be written as: 4^x + 1/(4^x) = 5/2 Now let y=4^x, to get: y + 1/y = 5/2 Multiplying ...
Unity method	8/16/2010
Q: I need to know how solved these problems. Please. 1)Margaret paid $87 altogether for a skirt and a ... A: 1. Not enough information. Knowing ONLy the total cost of . two items, we cannot determine the ...
not sure how to solve.	8/15/2010
Q: Need help with this problem. Solve ∛(3x+8) + 6 = 1 Need help with this problem. Divide ... A: 1. ∛(3x+8) + 6 = 1, subtract 6 from both sides: ∛(3x+8) = -5 . now cube both sides: ...
Solving a second-degree equation	8/14/2010
Q: The equation is 2x^2-6x+3=0. I'm having problems mainly because of the -6x in the middle. I've ... A: Do you know how to factor quadratics? If so, and you tried, you would find that this is not ...
Algebra	6/10/2010
Q: 1. Suppose you are an event coordinator for a large performance theater. One of the hottest new ... A: I think you meant: "-0.2x^2 + 14x + 5" -- Yes? If so, then... a) down, since the coefficient of ...
Math-CriticalThinking	6/7/2010
Q: Five-digit sum. Find the sum of all five-digit numbers that are formed by using the digits 1, 2, 3, ... A: There are 5!=120 differnt permutations of "12345" (i.e. 120 different5-digit numbers). Each digit ...
algebra word problems please help soon	6/6/2010
Q: The recipe for a loaf cake calls for 3/4 (fraction) pound of jelly beans in assorted colors. If 20 ... A: I gather the recipe is 3/4 of a pound of jelly beans PER CAKE...yes? If so, then 20 cakes will ...
algebra	6/5/2010
Q: I would like to ask you that may I denote the determinant of any matrix(say A) by this symbol \|det ... A: Your teacher is correct. det(A) is the determinant of matrix A, as is \|A\|. However, \|det(A)\| would ...
Dimensions	1/6/2010
Q: A bookshelf is to be constructed with 4 shelves. The height is 3 feet more than the width. ... A: In that case... Let x=the width of the bookshelf (in ft), so that x+3 = the height (in ft) 4 ...
algebra 1	1/1/2010
Q: i need help understanding Growth and Decay. one example would be: Determine the amount of an ... A: I gather you are familiar with the compound interest formula: A=P(1+r/n)^(nt), yes? P=Principal ...
Algebraic Equation	12/31/2009
Q: The area of a rectangle is 48cm^2. If its length is increased by 1cm and its breadth is decreased by ... A: Let L=the length of the rectangle, W=the width. We have LW=48, and L+1=W-1, since a square has all ...
Calculating cube roots	12/28/2009
Q: Reading about a local (Norfolk, UK) 18th C mathematical genius, Richard Porson, I found that as a ... A: Check these sites. http://www.slideshare.net/greymatters/extracting-cube-roots-mentally ...
Elimination Method	12/25/2009
Q: I am a college student and I need help, pronto, with an equation, please and thank you. 2x-4y=34 ... A: I gather you want to solve the system of equations, for x & y...yes? Two popular ways: 1. By ...
Abe, could you please help me with these problem I can't seem to get it right.	8/13/2009
Q: Problem #1 Find the values of x and y that solve the following system of equations: -5x – 7y = -14 ... A: 1. -5x – 7y = -14 & -6x – 5y = 7...solve by "elimination"...multiply the 1st equation by -6 and the ...
Algebra-Quadratic Equations	7/22/2009
Q: : I have no problem solving the equations but I am having difficulty with one of my problems: ... A: I am not 100% sure I know what you want, but how about this... Suppose I want to construct a ...
algebra	7/20/2009
Q: What are the asymptotes of the functions f(x)=4^x" and "g(x)=log5x?" Please explain. I do not have ... A: f(x)=4^x simply means f(x), or y, is assigned a value for each x-value you can use. So, for ...
math	7/19/2009
Q: Ako po ay perplexedly our pinagaaralan now to solve systems of Linear equations by eliminating ... A: If we simply add the two, we will eliminate the y's: 4x=8, so x=2...now we can substitute x=2 into ...
Simultaneous Equations and the Physical World	7/16/2009
Q: Solve the following systems of equations. 1. x-y=3 2x-y=-1 Answer: Show your work: 2. 2x+4y=10 ... A: 1. x-y=3 ==> x=y+3, now substitute that into the other equation. .. 2(y+3)-y=-1 ==> 2y+6-y=-1 ==> ...
HELP!	7/12/2009
Q: I have a few Algebra questions. I really need some help. 1. 2 binomial factors of 6s^2+40s-64 2. ... A: 1. First look for common factor(s)...in this case a "2" .. ==> ...
algebra	7/11/2009
Q: The points (1,3),(2,5),(8,17), (50,101) and (1000,2001) all lie on line M. The points ... A: b) Simply find the equations of each line,, then solve to solve .. to see where they intersect. ...
Algebra	7/10/2009
Q: Plot the graph of the equations 2x-3y=5 and 4x-6y=21. I can't remember how to solve these equations ... A: You can plot linear functions by either expressing them in the form y=mx+b or simply finding two ...
algebra	7/10/2009
Q: having to form equation for 2 lines. I have completed it for one of the lines, but having difficulty ... A: All we need are 2 points on the line, so use any 2 of the 3 points. How about using the first 2: ...
Slope-Intercept Form and Perpendicular	7/5/2009
Q: Write an equation in slope intercept form for a line that passes through the give point and is ... A: Since y=3 is a horizontal line (with a zero slope), a perpendicular line to it would be vertical ...
linear equations	7/2/2009
Q: a fruit grower has 200 acres of land available to raise two crops, A and B. It takes 1 day to trim ... A: Let x=# of acres of Crop A ... y=# of acres of Crop B "<=" means "less than or equal to" x + y <= ...
Simple Algebra Question	6/11/2009
Q: Abe- Hope all is well. My question will probally take you about 30 seconds to figure out. It is not ... A: You have the right idea! We just need parentheses: (x-2)/x=0.991 Now multiply by x on both sides: ...
algerbra	6/1/2009
Q: Tim and Tom mix 2 kinds of feed for pedigreed dogs they wish to make 22 pounds of feed worth .44 per ... A: Let x=# of pounds of the cheaper feed used, so then 22-x=# of pounds of the other feed used (since ...
Right-Triangle Trigonometry	5/31/2009
Q: I'm so sorry to keep asking so many questions, but I have no one else who can help me. I basically ... A: No problem asking me! :-) You have a right triangle there, so you can use your right triangle ...
algebra	5/30/2009
Q: we are doing co-ordinates of the points on a line graph.I an a little confused. The question is The ... A: a) All we need are two points to determine a line. Let's use the - the first two: (1,3) & ...
Math	5/29/2009
Q: By looking at an equation, how do you decide if it is a linear equation (graph is a straight line) ... A: A linear equation is one that can be put into the following form: Ax + By = C ... i.e. the variables ...
Algebra 2 Questions	5/27/2009
Q: Could you please help me with these problems? I have an idea of how to do these, but am not entirely ... A: Wow, you have many questions there...looks like a HW list! How about I do 3 of them so you get the ...
Long Algebraic Method (square roots)	5/24/2009
Q: I'm attempting to tutor a seventh grade student in finding the square root of large numbers using ... A: Here are some links that should be helpful: http://math.arizona.edu/~kerl/doc/square-root.html ...
Linear/Graphing problems	1/12/2009
Q: I have this question which I just can't figure out how they got the solution. Q. The equation of ... A: Since we can express it as y=mx+b, we first need the slope... slope, ...
7th grade algebra	1/9/2009
Q: David started across a lake 15 miles wide in his fishing boat at 10 miles per hour. He had to row ... A: Since distance = rate X time, we can set it up as follows: Let t = the total time the trip took, ...
Algebra	1/6/2009
Q: I have one bucket and 2 faucets. One faucet can fill the bucket alone in 6 minutes. The other ... A: Since work = (rate of work)x (time), we get: The rate of work for the first faucet is 1 bucket in 6 ...
algebra	1/4/2009
Q: question factoring question 1 x2-6x-16=0 question 2 6x2+42x=0 A: I gather you mean by "x2" "x squared" - yes? It is usually written x^2. So... 1. x^2 -6x - 16 = ...
Algebra Distance Word Problems	1/2/2009
Q: This is an example of the type of problem I'm having trouble with. I'm looking for more than just ... A: Sorry to hear this problem, or ons like it, have been causing you so much grief! I hope I can help! ...
Area	12/29/2008
Q: A spider web has an arc of a quarter circle and is 20 inches in length. Calculate area covered by ... A: We need to know the radius of the arc...since it has a length of 20 inches, and we know it is 1/4 of ...
Pre-Cal	9/1/2008
Q: Getting the zero of a function. 4X^3-24X^2-X+6 A: So, you want to solve 4X^3-24X^2-X+6=0... Factor by grouping: 4x^2(x-6)-1(x-6)=0 Now factor out the ...
algebra	7/24/2008
Q: how can solve this : E like the greek symbole divided by square root of 10. E/V10 A: I do not understand the problem. What is "E" supposed to be? Do you mean "e" the base of the ...
Algebra	7/23/2008
Q: I'm new to algebra, word problems are difficult for me to understand. Ex: Sally wishes to mix ... A: Let x=the # of lbs of raisins needed, and let y=the # of lbs of granola needed. So... x+y=6, and ...
Algebra	7/21/2008
Q: For all x>0 and y>0, the radical expression of the square root of x/3 square root of x- square root ... A: I do not understand what you have written...is it supposed to be an equation? If so, there should ...
interval notation	7/20/2008
Q: How do you know when to use interval notation for numbers on a number line? And when it is simply ... A: Interval notation is used to spcecify a range of values, not just 1 or 2 values. For example: 1. ...
college algebra	7/18/2008
Q: I'm not understanding factoring. My instructor wants us to factor these problems completely and I am ... A: The first thing to look for when factoring is common factors. 1. x^10 y^3 - 4x^9 y^2 - 21x^8 y, ...
writing a system of equation	7/15/2008
Q: How can i write a system of equation with a unique solution, an infinite number of solutions, and ... A: 1. 9/15 = x/202, where x=the number infected out of the 202. -- solving for x: x=(9/15)*202=121.2, ...
9 yr olds strange math questions	7/12/2008
Q: my daughter wants to know,if your driving 60 miles per hour,or really any amount of mph, what is the ... A: The speed problem is the easy one! :-) 60 miles/hour = 88 feet/sec, in case you want to know how to ...
Cost	7/11/2008
Q: A square lot contains 54,756 square feet is to be enclosed by a close board fence 12 feet high. The ... A: Hmm, $13 per THOUSAND board ft sounds rather unrealistic...perhaps it is $13 per thousand square ...
Solving a Pattern	7/9/2008
Q: I am trying to solve the following pattern for y x y 1 8 2 14 3 4 24 5 28 I ... A: Questions like these often have many different answers...there are lots of different functions that ...
linear equation in two variables	7/8/2008
Q: I have a study question and I can't figure out how to approach solving it. I cannot get the correct ... A: If we want the vertical line x=2 to be perpendicular to the segment, then the segment must be ...
Word Problem	7/6/2008
Q: I am stuck on finding a formula to solve the following word problem: If Sam can do a job in 4 days ... A: Since work = rate x time... The rate Sam can work is 1/4 (of a job/day), Lisa works at the rate of ...
algebra- absolutes	7/5/2008
Q: I don't know how to make an absolute sign, so instead I'll use this: / OK? I don't know anything ... A: You can use "\| \|" (i.e. the vertical bar for absolute value). It seems to me the problem you pose: ...
radical expressions	1/18/2008
Q: How is adding radical expressions similar to adding polynomial expressions? How is it different? A: It is similer in that you still have like terms: for polynomials, like terms have the same ...
algebra help	1/14/2008
Q: i dont understand the elimination method at all.. i need help big time.! 2x-y=2 3x+4y=25 A: The elimination method requires that we multiply one or both equations by a non-zero number so that ...
algebra question	1/13/2008
Q: can't figure out how to solve for X. a(x+c)=bx+d thanks A: a(x+c)=bx+d, now distribute... ax+ac=bx+d, subtract bx from both sides to get ax-bx+ac=d, now ...
algebra	1/12/2008
Q: My name is Diashamar. I would like to know how to solve the problem using the ... A: The idea is to multiply one (or both) equation(s) by numbers so that when they are added together, ...
cost equation	1/10/2008
Q: 1. In this problem, we will analyze the profit found for sales of decorative tiles. A demand ... A: You have quite a few questions here! Please narrow it down some...perhaps only the most important ...
polynomials	1/9/2008
Q: How do you determine if a polynomial is the difference of two squares? A: You look for excactly "the difference of two square"... For example, x^2 - 25...notice that the ...
Linear Combinations	1/8/2008
Q: I need help with this particular problem on my math homework! 5e + 4f = 9 4e + 5f = 9 Thank you!! A: I gather the problem is to solve for 'e' and 'f'... One way is by "elimination"... multiply the 1st ...
synthetic divison	1/2/2008
Q: hey im having alot of trouble with this problem. * means to the 3rd in the exponent and ^ means to ... A: First, the common notation for exponentiation is: x^n = "x raised to the power of n" So, the ...
square root	12/28/2007
Q: How do I find the square root of 1152? A: Depends on what you are allowed to use. If a calculator, then use the "square root" key. If no ...
value definitions	12/26/2007
Q: I am studying absolute value inequalities and am experiencing an embarassingly fundamental ... A: I think the phrase: 'what real numbers are closer to 0 than 4 is?' is quite confusing! To explain ...
Algebra	12/25/2007
Q: Simplify the radical:. ã63xy11 /ã7xy Assume that all variables represent positive numbers. ... A: I am not sure I understand...let me rephrrase it and tell me if it is what you mean. I will use the ...
Cost of equity w/flotation	6/7/2007
Q: Javits & Sons’ common stock is currently trading at $30 a share. The stock is expected to pay a ... A: Wow, I just found this question of yours from the summer! I had "been on vacation" from AllExperts ...
algebra question	6/2/2007
Q: Explain how to find the coordinates of a point in the rectangular coordinate system. A: Check these webaites: http://www.learningwave.com/lwonline/algebra_section2/alg_coord.html ...
travel problem	5/31/2007
Q: I know the basic travel problem can be solved through d=rt, but I don't know how to solve the ... A: Since the speeds are relative to the riverbanks the downstream average speed is 2.75 mi/hr, and the ...
problems graphing	5/28/2007
Q: I need to solve each system by graphing for example 3x-6y=9 x-2y=3 and Find values for m and b in ... A: 3x-6y=9 & x-2y=3 It is tough for me to show here how to solve this by graphing. I'll just briefly ...
Exponential problem	5/24/2007
Q: Mantell, My problem is: I would like to be able to produce a list of numbers derived exponentially, ... A: I think you want to use the sum of a geometric progression. A+Ar+Ar^2+...+Ar^n = A[1-r^(n+1)]/[1-r] ...
Zeros of a Function	1/1/2007
Q: f(x)=-x^2+3x+6. I would greatly appreciate the help.Thanks. A: The usual way is to factor, but since this doesn't factor so well, we just use the quadratic ...
Difficult Algebra Problems	8/6/2006
Q: I'm hoping you could help me out with a few of algebra problems I am having difficulty with. I ... A: a) I gather you mean the "square root"...yes? -- it can be written as: (w-3)^(1/2) = (4w+15)^(1/2) ...
Intermediate Algebra	6/7/2006
Q: Help! I need Intermediate Algebra help. I would appreciate any help you can provide. I have ... A: Check these links for how to use Cramer's Rule...it is tough for me to type all that and make it ...
circles	6/6/2006
Q: rhombus ABCD is inscribed in a circle. what is the degree measure of arc AB? explain your reasoning. A: The only rhombus that can be inscribed in a circle, and have all 4 vertices on the circle, is a ...
hello	6/2/2006
Q: ma'am/sir, could you pls help me? i have just conducted my thesis and need to find some related ... A: Not sure about web-sites...I suggest you ask in related newsgroups for highs school mathematics, ...
Algebra	5/30/2006
Q: 1. The monthly revenue achieved by selling x boxes of candy is calculated to be $ x(5-0.05x). The ... A: 1. Profit=Revenue-Cost=x(5-0.05x)-1.5x=3.5x-0.05x^2 -- which is maximized at ...
What is needed to know for 9th grade algebra etc.	5/20/2006
Q: I would like to know what is required to know and what I will learn in the ninth grade algebra ... A: Algebra is a generalization of arithmetic...so you need to know all your arithmetic very well...like ...
ALGEBRA	1/8/2006
Q: 8k - 5n = 8r 3u + 2o = 189 5d + 2c = 6m 5L + 4m = 23b 3r - m = 3u 3k - 4i = 2i 3n - 3o = c o - c ... A: What is the "answer" for each "letter"? I gather you are to take each equation and solve for a ...
Helping my daughter with math homework	1/4/2006
Q: Plane A left the airport at 3:30 p.m. traveling west at 450mph. Plane B left the same airport at ... A: Let t=the time, in hours, Plane B is in air. Thus, t+1.5=the time Plane A is in air. We want: ...
Algebra Equation	1/3/2006
Q: I am trying to help my neice find the answer to this equation 3 1/3x + 1 5/6 =4 1/2, but I do not ... A: I'd change the mixed numbers to improper fractions: 3 1/3x + 1 5/6 = 4 1/2 becomes (10/3)x + 11/6 = ...
finding the roots...............	1/1/2006
Q: find all the roots of the equation: x^3-343=0 solve the following equation for x and y: ... A: 1. x^3=343 ==> x=343^(1/3)=7[cos(2PIk/3)+isin(2PI*k/3)], for k=0,1,2 ==> x= ...
Systems of Equations	12/28/2005
Q: Which expression can be substituted for x in the top equation of the sytstem below to solve the ... A: If we take the 2nd equation and solve for x, we get x=4y-4...then substitute that into the 1st ...
Simple equation needed	9/19/2005
Q: I am looking for a simple equation. If I have 1,000,000 widgets and need to figure out how many ... A: I gather you mean split up your 1,000,000 widgets into a 3 to 2 ratio...yes? If so, then we want ...
radius of a circle	9/13/2005
Q: I have the chord length (84) and the height of the sector (11) but need the radius. I believe the ... A: So, the formula is: c=sqrt[4h(2r-h)] So we square both sides: c^2=4h(2r-h) Distribute: c^2=8hr-4h^2 ...
inverse functions	9/7/2005
Q: I am taking Calc. 1 and we just started. We are reviewing right now and I am having trouble ... A: Sure...check these sites: http://www.purplemath.com/modules/invrsfcn.htm ...
why	9/5/2005
Q: why abstract algabra is important? do it has real applecition? A: What good is "Abstract Algebra"? At first, it may seem like this class is only an exercise in ...
algebra	9/3/2005
Q: Write an equation using four 4's where the answer is 31. You may use any operation, parenthesis, ... A: Here are some solutions: 1. ((4+sqrt 4)!+4!)/4!=31 2. 4!+(4!+4)/4 3. ...
two nearest number to ten thousand	8/28/2005
Q: determine the two nearest number to 10,000, which are exactly divisible by 2, 3, 4, 5, 6, 7. A: Al we need to do is check the multiples of 1257=420 (since 12 is a multiple of 2,3,4 and 6) ...
algebra	8/23/2005
Q: solve by elimination or substitution method? 2x-y+z = 10 x+2y-z = 12 x+y-2z = 6 A: The system can be solved either way... I'll use substitution only because it is easier to type. ...
Simultaneous Equations	6/1/2005
Q: Please could you assist me in solving Simultaneous Equations, currently I have no idea how to do ... A: Check these sites for help & examples: http://www.allaboutcircuits.com/vol_5/chpt_4/14.html ...
gold coin algebra/fraction problem help!	5/27/2005
Q: I have a word problem I can't figure out... hank had to give a guard 1/3 of his coins to leave town. ... A: I gather you mean that at each stage he gave that fraction of money he had left...yes? If so, then ...
given f(t)=(2t-3)^2 find the...	2/2/2005
Q: given f(t)=(2t-3)^2 find the sum of all values t that satisfy f(t)=3/4. is the answer o? A: We have: (2t-3)^2=3/4 ==> 4t^2-12t+9=3/4 ==> 16t^2-48t+36=3 ==> 16t^2-48t+33=0 ==> t^2-3t+33/16=0 ...
marcia Kleinz hikes down to...	2/1/2005
Q: marcia Kleinz hikes down to the bottom of Bryce Canyon, overnight, and returns the next day. her ... A: Seems to me there is not enough info! Here's is what I set-up: let x=the one-way distance t1=the ...
algerba	1/30/2005
Q: could you please soleve this for me: 1/3x + 17y=43 10x+3/7y=32 i don't know where to start. A: I gather the equations are: (1/3)x + 17y=43 10x+(3/7)y=32 ....Yes? If so, then we can solve either ...
help	1/29/2005
Q: need help how many sides does a dodecagon have if it is regular what are the interior and exterior ... A: 12 sides... the interior angle measure of an n-sided regular polygon is 180(n-2)/n degrees...so, ...
y-intercept	1/26/2005
Q: Ok i have this really big math test tomorrow and i really need your help and fast! Please! Ok i need ... A: I am not sure what you mean by "...take a whole number and turn it into a fraction so i can multiply ...
algebra	1/23/2005
Q: what is the answer to n[n+11(y-1)]= and [n+(y-1)][n+10(y-1) please help i am really ... A: What is the question? Simplify or solve? If solve, they are incomplete... If simplify, then: 1. ...
Linear Algebra	1/19/2005
Q: We have this system, and we are trying to solve it. x+2y-z=2 2x+5y-3z=1 x+4y-3z=3 We have tried ... A: What did your calculator give? What way(s) did you try? Gaussian elimination? Inverse matrix? This ...
a GRE question	1/17/2005
Q: Average of Test Scores in Class R Average score for the boys 90 Average score for the girls 81 ... A: Since the average for the class is closer to the average for the girls, there must be more girls in ...
Word Problem(Algebra 1)	1/16/2005
Q: I'm having trouble answering this word problem. I hope you could help me sove it ASAP. I hope you ... A: Let x=the number of 5 point questions, and y=the number of 2 point qustions. So, x+y=38 AND ...
Elimination method of solving a linear equation	1/12/2005
Q: I am having trouble understanding how to solve linear equations by using the elimination method. I ... A: We make the selection based upon which variables we select to eliminate and what the least common ...
Polynomial Long Division	1/9/2005
Q: I'm having trouble with Polynomial Long Division, especially with this problem. How do you do it? ( ... A: ..what is it?), Long division of polynomials is similar to ordinary long division. Here are some ...
algebra	1/6/2005
Q: the dowry of francis wife is 100 aurie more than the property, the square of the dowry is 400 more ... A: Let x=the dowry amount, y=property (value?) Thus, x=100+y and x^2=400+y^2 substituting x=100+y into ...
clearing equatioms	1/4/2005
Q: i'm homeschooled and my mom doesn't know how to do algebra, i get the basics but i need help with ... A: ..where are you from?), 1. x/2+x/3-x/4+3x/10-5x/12=7 the LCD (LCM of 2, 3, 4, 10, and 12) is 60 so ...
The substitution, addition, or subtraction method	12/30/2004
Q: I have this problem that i could really use soem help with, I understand the problem but I dont ... A: One way to solve this is to take one equation and solve for one of the variables, then substitute ...
Graphs	12/27/2004
Q: 8. Your are shopping for cassettes and CDs. Cassettes cost $7, CDs cost $14, and you have $28 to ... A: Let x=# of cassettes you buy & y=# of CD's you buy. Thus, 7x+14y=28 (assuming no tax, and you spend ...
d^2y/dx^2 = 2 which is positive...	1/26/2004
Q: d^2y/dx^2 = 2 which is positive hence the turning point is a minimum, can you find the turning ... A: a) I'll use 't' instead of '0'...so, x=t(6-t)=6t-t^2 dx/dt=6-2t=0 ==> t=3, with x''=-2, thus t=3 ...
Quadratic equations	1/22/2004
Q: How do I start to solve the equation (7t + 6)^2 = 19 A: Two ways of doing this that are OK... 1. expand the left hand side to get: 49t^2+84t+36=19 then ...

All Questions in This Category

Algebra

All Answers

Answers by Expert:

Ask Experts

Volunteer

Abe Mantell

Top Expert on this page

Expertise

Hello, I am a college professor of mathematics and regularly teach all levels from elementary mathematics through differential equations, and would be happy to assist anyone with such questions!

Experience

Over 15 years teaching at the college level.

Organizations
NCTM, NYSMATYC, AMATYC, MAA, NYSUT, AFT.

Education/Credentials
B.S. in Mathematics from Rensselaer Polytechnic Institute
M.S. (and A.B.D.) in Applied Mathematics from SUNY @ Stony Brook

Encyclopedia

Browse Answers: