Expert: Sherman D. - 10/31/2008

Question
QUESTION: Can you please check these for me? I am more confident of my answers this time. Thank you ;)


1) Solve the following system of equations:

x + y = 6
y = 2x

answer: (2, 4)


2) Solve the following systems of equations:

2x - 3y = -13
y = 2x + 7

answer: (-2, 3)


3) Solve the following

x = 3y + 7
x = 2y - 1

answer: (-17, -8)


4) Solve

x + y = 6
x - y = -2

answer: (2, 4)


5) Solve

3x + 2y = 14
3x - 2y = 10

answer: (4, 1)


6) Solve

3x - 7y = 13
6x + 5y = 7

answer: (2, 1)



7) Solve

2x + 3y = -16
5x - 10y = 20

answer: {-20/7, -24/7}

8) Solve

5x = 6y + 40
2y = 8 - 3x

answer: {32/7, -20/7}


9) Solve
x - y + 3z = 8
3x + y = -2z = -2
2x + 4y + z = 0

answer: {1, -1, 2}


10) Solve

2x + 3y = 7z = 13
3x + 2y - 5z = -22
5x + 7y - 3z = -28

answer: (-1, -2, 3)


11) Solve

x + z = 3
z + 2y - z = 1
2x - y + z - 3

answer: (1, 1, 2)


12) Solve

x + 3y + 5z = 20
y - 4z = -16
3x - 2y + 9z = 36

answer: (0, 0, 4)


13) Solve

x + y = 4
x + z = 4
y + z = 4

answer: (2, 2, 2)


14) Solve
x - 3z = -5
2x - y + 2z = 16
7x - 3y - 5z = 19

answer: (4, -2, 3)



ANSWER: ) Solve the following system of equations:

x + y = 6
y = 2x

answer: (2, 4)
Correct.

-----------------------------------

2) Solve the following systems of equations:

2x - 3y = -13
y = 2x + 7

answer: (-2, 3)
Correct

----------------------------

3) Solve the following

x = 3y + 7
x = 2y - 1

answer: (-17, -8)
Correct

-------------------------------

4) Solve

x + y = 6
x - y = -2

answer: (2, 4)
Correct

--------------------------------

5) Solve

3x + 2y = 14
3x - 2y = 10

answer: (4, 1)
Correct

-----------------------

6) Solve

3x - 7y = 13
6x + 5y = 7

answer: (2, 1)

That should be (2,-1)

---------------------------

7) Solve

2x + 3y = -16
5x - 10y = 20

answer: {-20/7, -24/7}
Correct

-----------------------------

8) Solve

5x = 6y + 40
2y = 8 - 3x

answer: {32/7, -20/7}
Correct

-------------------------------

9) Solve
x - y + 3z = 8
3x + y = -2z = -2
2x + 4y + z = 0

answer: {1, -1, 2}
Correct

--------------------------------

10) Solve

2x + 3y = 7z = 13
3x + 2y - 5z = -22
5x + 7y - 3z = -28

answer: (-1, -2, 3)
Correct

---------------------------------

11) Solve

x + z = 3
z + 2y - z = 1
2x - y + z - 3

answer: (1, 1, 2)
Correct, but you should type it correctly next time.

---------------------------------

12) Solve

x + 3y + 5z = 20
y - 4z = -16
3x - 2y + 9z = 36

answer: (0, 0, 4)
Correct

---------------------------------

13) Solve

x + y = 4
x + z = 4
y + z = 4

answer: (2, 2, 2)
Correct

------------------------------

14) Solve
x - 3z = -5
2x - y + 2z = 16
7x - 3y - 5z = 19

answer: (4, -2, 3)
COrrect

instead of asking me if its correct, you can go to www.quickmath.com, click on Solve under Equations, click Advanced, then make sure the variables on the right are correct, then click solve.

---------- FOLLOW-UP ----------

QUESTION: I previously mis-typed these two.. Can you please check them for me?

1) Evaluate the determinant in the matrix |7, -2... 9, -5|

I think its C

a) 20
b) -11
c) 42
d) -22

2) Evaluate the determinant in the matrix |1, -8   -3, 2|

I think its A

a) 20
b) -11
c) 42
d) -22

Answer
You really need to learn to type it so i can understand it.

1) Evaluate the determinant in the matrix |7, -2... 9, -5|

I think its C

a) 20
b) -11
c) 42
d) -22

7,-2
9,-5

det = (7 * -5) - (-2 * 9) = -35 + 18 = -17

i get -17.

--------------------------------

2) Evaluate the determinant in the matrix |1, -8   -3, 2|

I think its A

a) 20
b) -11
c) 42
d) -22

1,-8
-3,2

det = (1 * 2) - (-8 * -3) = 2 - 24 = -22
ANS : D.