Since x^2>=0 it redueces to |x-x^2|=2
(x-x^2) is always less than zero if x is an integer (very easy to prove)
So it reduces to
x=2 or x=-1
x=2 (solve as (1))
x=-2 (by symmetry. You can solve it too like before)
I disagree this is too hard for GMAT. I say it is a perfect GMAT question.
Keep on asking, and it will be given you;
keep on seeking, and you will find;
keep on knocking, and it will be opened to you.