# Thread: Solving a square equation?

1. ## Solving a square equation? SOLVED

Hi!

I´m doing maths at the moment and I´m having trouble solving the following question:

4 (x+7)^2 = 36

I started of by just taking the root of both
so it became:

2 ( x + 7) = 6

And now I don´t know what to do, I´m trying to solve this by the help of the quadratic formula.

2. Careful! Remember that $\displaystyle (6)^2=(-6)^2=36$, so $\displaystyle \sqrt{36}=\pm 6$

Once you change your method to incorporate the two possible solutions, your method would work However, I would just have divided both sides of the equation by $\displaystyle 4$ at the beginning:

$\displaystyle (x+7)^2=9$

Now take the square root of both sides, but remember that you should obtain two solutions as $\displaystyle \sqrt{9}=\pm{3}$

You could choose to do this using the quadratic formula, but it would be unnecessary; you'd have to expand the brackets and then rearrange terms - this approach is far simpler!

3. Hi! Thank you both for the great explainations!