$\left\{\begin{matrix}x=\frac{z}{5y}\text{, }&y\neq 0\\x\in \mathrm{C}\text{, }&z=0\text{ and }y=0\end{matrix}\right.$

$\left\{\begin{matrix}y=\frac{z}{5x}\text{, }&x\neq 0\\y\in \mathrm{C}\text{, }&z=0\text{ and }x=0\end{matrix}\right.$

$\left\{\begin{matrix}x=\frac{z}{5y}\text{, }&y\neq 0\\x\in \mathrm{R}\text{, }&z=0\text{ and }y=0\end{matrix}\right.$

$\left\{\begin{matrix}y=\frac{z}{5x}\text{, }&x\neq 0\\y\in \mathrm{R}\text{, }&z=0\text{ and }x=0\end{matrix}\right.$