\(\left(y+1\right)\left(xy-1\right)=3\)
Suy ra \(\left\{{}\begin{matrix}y+1=3\\xy-1=1\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y+1=-3\\xy-1=-1\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y+1=-1\\xy-1=-3\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y+1=1\\xy-1=3\end{matrix}\right.\)
Suy ra \(\left\{{}\begin{matrix}y=2\\2x-1=1\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y=-4\\-4x-1=-1\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y=-2\\-2x-1=-3\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y=0\\x\cdot0-1=3\end{matrix}\right.\) (loại)
Suy ra \(\left\{{}\begin{matrix}y=2\\x=1\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y=-4\\x=0\end{matrix}\right.\) hoặc \(\left\{{}\begin{matrix}y=-2\\x=1\end{matrix}\right.\)
\((y+1)(xy-1)=3\)
\(\Rightarrow\)\(y+1;xy-1 \) là Ư(3)
\(Ư\left(3\right)=\left\{\pm1;\pm3\right\}\)
Ta có thể xét các trường hợp
\(y+1=1;xy-1=3\)\(\Rightarrow\)
\(y+1=-1;xy-1=-3\)\(\Rightarrow\)
\(y+1=3;xy-1=1\)\(\Rightarrow\)
\(y+1=-3;xy-1=-1\)\(\Rightarrow\)
(tự xét nha 10 giờ rồi mình buồn ngủ lắm)
