think it easy: 1) x-y=1/2 .. Positive => x>y since can be: (+,+) or (+,-) or (-,-) : Insuff 2) x/y>1 since x/y>0 since (x,y) have to have the same sign: (-,-) or (+,+) : Insuff Let's see what we could earn putting together: 2) finding the conditions of existence of the second expression ...