The answer is:
below
Work/explanation:
The square of a negative number is always a positive number :

where b = the square of -a
The thing is, the square of a positive number is equal to the square of the same negative number :

So if we take the square root of a number, let's say the number is 49 - we will end up with two solutions :
7, and -7
This was it.
Therefore, this is the answer.