Quote:
|x|=|y||x|=|y| . So, x=−yx=−y or x=yx=y. If x=−yx=−y, then x+y2=−y+y2=0=integer
May i ask, the way i thought was: x= -y , only with condition that both are 0. if we put 1 =(-1), it be wrong. or any other integer. Can you help to find where i am wrong? Thank you!