prove the limit of $f(x,y)=\frac{x^3−y^3}{x^2−y^2}$ exists with an $\epsilon - \delta$ prove Given the function $f(x,y)=\frac{x^3−y^3}{x^2−y^2}$. Defined by $x^2\neq y^2$ and $(x,y) \in \Bbb R$.
Proof that $\lim\limits_{(x,y) \rightarrow (0,0)} f(x,y)$ exists.

I found that the limit went to $0$. And I was trieing to prove this with an $\epsilon$ $ \delta$ prove, but I'm stuck.

I got: 

Let $\epsilon &gt; 0$ be given, take $\delta= ....$.
Than $|(f(x,y)-L|$=$|\frac{x^3-y^3}{x^2-y^2}|$= $|\frac{x(x+y)+y^2}{x+y}|$=$|x+\frac{y^2}{x+y}|$

I don't know how to go on.
You can't prove a limit exists when it doesn't take for example $y\to - x$
You can't prove a limit exists when it doesn't take for example $y\to - x$