Giải hệ pt: 1)\(\hept{\begin{cases}1+x^3y^3=19x^3\\y+xy^2=-6x^2\end{cases}}\)
2)\(\hept{\begin{cases}\sqrt{3x}\left(1+\frac{1}{x+y}\right)=2\\\sqrt{7y}\left(1-\frac{1}{x+y}\right)=4\sqrt{2}\end{cases}}\)
3)\(\hept{\begin{cases}x^2+y^2+xy+1=4y\\y\left(x+y\right)^2=2x^2+7y+2\end{cases}}\)