$\left\{\begin{matrix}x=\frac{yz}{y-z}\text{, }&y\neq z\\x\in \mathrm{R}\text{, }&y=0\text{ and }z=0\end{matrix}\right.$

$\left\{\begin{matrix}y=\frac{xz}{x-z}\text{, }&x\neq z\\y\in \mathrm{R}\text{, }&x=0\text{ and }z=0\end{matrix}\right.$