# Math Help - Question regarding functions

1. ## Question regarding functions

I am having some difficulty solving this question, any help would be greatly appreciated.

2. Originally Posted by Solid8Snake
I am having some difficulty solving this question, any help would be greatly appreciated.

If $f(t)=\frac{t-x}{t+y}$, then
$f(x+y)=\frac{x+y-x}{x+y+y}=\frac{y}{x+2y}$
$f(x-y)=\frac{x-y-x}{x-y+y}=-\frac{y}{x}$
Thus, $f(x+y)+f(x-y)=\frac{y}{x+2y}-\frac{y}{x}=\dots$