\(x\left(y-1\right)=1\)
\(\Leftrightarrow x;y-1\inƯ\left(1\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y-1=1\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\y-1=-1\end{matrix}\right.\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\y=0\end{matrix}\right.\end{matrix}\right.\)
Vậy --