Answer:
1 and -1
Explanation:
The correct answer is 1. The square root of a (real) number is always taken to be the non-negative square root (this allows the square root operation to be a function).
However, if the question is saying it isn't 1, then it wants you to answer 1 and -1, because both square to 1. A better way to word the question would be "For which values of x is x^2 equal to 1?"