$1. \begin{cases}x^{2}+xy+x+3=0 \\ (x+1)^{2}+3(y+1)+2(xy-\sqrt{x^{2}y+2y})=0\end{cases}$
$2. \begin{cases}x^{2}+1-y\sqrt{x+y}=y \\ x^{2}(x+y-2)+x-2=5y\end{cases}$
$3. \begin{cases}1+xy-x^{2}y+x^{3}y-x^{4}=y \\ 1+2\sqrt{x-1}=3\sqrt[3]{2x-y}\end{cases}$