Bunuel wrote:
If x < y, which of the following must be true?
(A) x < y^2
(B) x^2 < y
(C) x^2 < y^2
(D) (x – y)^2 > 0
(E) x^3 > y
If x < y, then we can also conclude that x ≠ y.
If x ≠ y, then we can be certain that x - y ≠ 0
If x - y ≠ 0, then we can be certain that (x – y)^2 > 0
Answer: D
ASIDE: Another approach would be to take values that satisfy the inequality x < y, and plug them into each answer choice until we eventually eliminate all answer choices other than D.
I'll leave that to you...
_________________
Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
Many students fail to maximize their quant score NOT because they lack the skills to solve certain questions but because they don’t understand what the GMAT is truly testing -
Learn more