If0<x<y, what is the value of ((x+y)^2)/((x-y)^2)?
(1) x^2 + y^2=3xy
(2) xy=3
Answer is a. Please explain.
(1) x^2 + y^2=3xy
(2) xy=3
Answer is a. Please explain.
A should be good.
(x+y)^2 = x^2 + 2xy + y^2
(x-y)^2 = x^2 - 2xy + y^2
so,
x^2 + 2xy + y^2 / x^2 - 2xy + y^2
substituting 3xy we get,
3xy + 2xy / 3xy - 2xy
= -1
