Question

How do you solve `(x+4)^2=81`?

Answer 1

There are two possible solutions.

Explanation:

You can take the square root on both sides, but you have to remember, that a negative number, when squared, also gives a positive answer. In this case it's not so hard:

`(x+4)^2=9^2 or(x+4)^2=(-9)^2`

So: `x+4=9->x=5`
Or: `x+4=-9->x=-13`

Most people leave out the second solution, so...