Prepping for a calculus exam. In a past exam I saw the following question:

> 
> Determine whether the following function is continuous at $(0,0)$:
>  $$
> f(x,y)=
> \begin{cases}
> \frac{e^{xy}-1}{|x|+|y|}, & \text{if $(x,y)\neq$(0,0)} \\ 
> 0 & \text{if $(x,y)=$(0,0)}
> \end{cases}
> \
> $$
> 
> 
> 

Not sure where to begin.