if x and y are different integers and x^2=xy, which of the following must be true?
D.1 & 3 only
E.1,2 & 3.
I think the key phrase is "X and Y are different intengers".
1: 0^2=O. ANY INTENGER, always true.
2: ANY INTENGER^2=0^2, can not be, cuz if Y is zero, X must be something else, as stem says.
3: (-Y)^2=-Y.Y, can be true only if Y is zero, stem does not give such info.
thus only 1st...