i didnt get this how u consider X and Y values when it is given in the question
If (x-5)(y+2) this means that X = 5 and
Y = -2
thus XY = -10 and X > Y..
(x-5)(y+2) = 0 means that EITHER x=5 OR y=-2. For example, if x=5, then y can be any number. The same way, if y=-2, then x can be any number.
suggestion on your last comment. (x-5)(y+2) =0 means that x = 5 OR y =-2 (without the EITHER). Obviously both equalities COULD happen simultaneously, but they don't HAVE TO happen simultaneously in order for the equation in stem to be valid