simple but cnt understand

[manasi_sh]

Is x2 equal to xy?
(1) x2 – y2 = (x + 5)(y - 5)
(2) x = y
Ans B..
x2= x square and y2 = y square

[santsark]

From 1 you can get the value of Y, which is not sufficient to prove X^2 = XY.

But from 2 we know X=Y, so XY = X*X = X^2.