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

1 Answer
Jan 25, 2016

Answer:

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...