Question

If x−y=a and x+y=b, then x^2−y^2 is:

(A) a^2·b^2
(B) a^2+b^2
(C) a^2−b^2
(D) ab
(E) b−a

i got c is this right?

Answer 1

x^2-y^2 = (x-y)(x+y) = ab