[quote="haas_mba07"]If x = 3y, is x^2 > y^2?
1. y+x < x-y
2. x^2 = 9
hmmm..this question is different
Essentially it is asking if 9y^2 > y^2 . This is true for all numbers except 0
1. x+y < x-y . For this to happen y should be negative or both x and y should be negative. so x is not 0 which implies y is not zero so SUFF
2. states 9y^2 = 9y^2 so nothing new here. It is true for all values of y except 0 so INSUFF
I would go with A