The Quest for 700: Weekly GMAT Challenge

Each week Manhattan GMAT posts a 700 level GMAT question on our blog and follows up with the answer the next day. Are you up for the challenge?

If ab = x and a/b = y, and ab does not equal zero, then a² – b² =

(A) x(y – 1)(y + 1)/y
(B) xy – y/x
(C) x² – y²
(D) y(x² – 1/x²)
(E) (y + x)(y – x)/x