\(\Leftrightarrow\left\{{}\begin{matrix}x^2\left(xy+1\right)-y\left(xy+1\right)+xy+1=2\\\left(x^2-y\right)^2+xy+1=2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(x^2-y+1\right)\left(xy+1\right)=2\\\left(x^2-y\right)^2+xy+1=2\end{matrix}\right.\)
\(\Rightarrow\left(x^2-y+1\right)\left(xy+1\right)-\left(x^2-y\right)^2-\left(xy+1\right)=0\)
\(\Leftrightarrow\left(xy+1\right)\left(x^2-y\right)-\left(x^2-y\right)^2=0\)
\(\Leftrightarrow\left(x^2-y\right)\left(xy+1-x^2+y\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}y=x^2\\xy+1=x^2-y\end{matrix}\right.\) thay xuống pt dưới:
- Với \(y=x^2\) thay xuống pt dưới \(\Rightarrow x^3=1\)
- Với \(xy+1=x^2-y\) thay xuống dưới:
\(\left\{{}\begin{matrix}xy+1=x^2-y\\2\left(xy+1\right)=2\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}xy+1=x^2-y\\xy=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0;y=-1\\y=0;x^2=1\end{matrix}\right.\)
