If , then is equal…

MATHEMATICS · Single correct · A Level · Mathematics · Algebra and Functions · Algebra and Functions

Problem

f(x+ay, x-ay)=axy

, then

f(x,y)

is equal to (a)

xy

(b)

x^2-a^2y^2

(c)

\frac{x^2-y^2}{4}

(d)

\frac{x^2-y^2}{a^2}