Advanced Math/algebra

Advertisement


Question
I am studying for a test and am having trouble working a review question. the original problem is √(2x+7)-√(x+3)=1. I have worked it a couple of times and I am not able to find the correct answer. Thanks in advance

Answer
Hi Tom,

Well, follow through my algebra and see if you understand each step.

sqrt(2x + 7) = 1 + sqrt(x+3)

2x + 7 = x + 3 + 2sqrt(x + 3) + 1

x + 3 = 2sqrt(x + 3)

(x + 3)^2 = 4(x + 3)

x + 3 = 0  OR x + 3 = 4

so x = -3, 1

Now, for square root problems, you always have to plug your answers back in since things can go wrong. In this case, they both work, so the answer is

x = -3 ,1

I hope this helps,
Robi

Advanced Math

All Answers


Answers by Expert:


Ask Experts

Volunteer


Robi Bhattacharjee

Expertise

I can answer a variety of questions on mathematics. Questions on trigonometry, calculus(preferably single variable), algebra, geometry, and number theory will be answered. I cannot answer questions on abstract branches of mathematics such as group theory. I also cannot answer questions on statistics. In number theory, I can answer questions on congruences, prime numbers, units, functions, and the riemann-zeta function.

Experience

I have studied advanced math my entire life. I started calculus in sixth grade. I have attended numerous math competitions and I am attending math organizations such as the San-Diego math circle. Also, this year I have been invited to the USAMO which is a prestigious math competition (Every year the USAMO invites 500 students from across the USA to participate in this competition. The top 6 go to represent the USA in the International Math Olympiad).

Organizations
I am in the San Diego Math Circle

Education/Credentials
I am entering high school and have received a perfect score and the STAR test 5 times in a row. I also have gotten recognitions in the AMC 10, AIME, Math Counts, and ARML. Additionally, I have won the San Diego Math Olimpiad twice in a row.

©2012 About.com, a part of The New York Times Company. All rights reserved.