Giải hệ phương trình:
1)
$\left\{\begin{matrix} x^3+2y^2-(x^2+x+4)y+x^2+xy^2-2=0 &\\ x^3+y^2-x^2y+x+xy^2-y=0 \end{matrix}\right.$
2)
$\left\{\begin{matrix} \sqrt{4-x}+\sqrt{y+8}=y^2+7x-1 &\\ \sqrt{2(x-y)^2+6y-2x+4}-\sqrt{x}=\sqrt{y+1} \end{matrix}\right.$
3)
$\left\{\begin{matrix} \sqrt{xy+(x-y)(\sqrt{xy}-2)}+\sqrt{x}=y+\sqrt{y} &\\ (x+1)(y+\sqrt{xy}+x(1-x))=4 \end{matrix}\right.$