Math question, any help is appreciated:)

Test Preparation
1

This question is from the october test.

If a+a=b^2, what is a+a+a in terms of b?

I have always struggled on the SAT with expressing variables in terms of each other. I know the right answer to the question (3/2b^2) but I was wondering if one of you could explain to me the process of expressing one variable in terms of the other.

Thanks!

2

Given a+a = b^2 is the same as 2a = b^2 then a =b^2/2. So now you are asked what a+a+a is. You know a=b^2 so substituting that into a+a+a gives you b^2/2 + b^2/2 + b^2/2 which is 3b^2/2.