$\left\{\begin{matrix}x\in \left(-\frac{z}{z-2},0\right)\text{, }&\left(z<0\text{ and }y\neq 0\right)\text{ or }\left(z>2\text{ and }y\neq 0\right)\\x>-\frac{z}{z-2}\text{, }&z<2\text{ and }z>0\text{ and }y\neq 0\\x<0\text{, }&z\leq 2\text{ and }z>0\text{ and }y\neq 0\end{matrix}\right.$

$\left\{\begin{matrix}z\in \left(0,\frac{2x}{x+1}\right)\text{, }&\left(x<-1\text{ and }y\neq 0\right)\text{ or }\left(x>0\text{ and }y\neq 0\right)\\z<\frac{2x}{x+1}\text{, }&x>-1\text{ and }x<0\text{ and }y\neq 0\\z>0\text{, }&x<0\text{ and }x\geq -1\text{ and }y\neq 0\end{matrix}\right.$