\(xy-x=3\)
\(\Rightarrow x\left(y-1\right)=3\)
\(\Rightarrow x;y-1\inƯ\left(3\right)\)
\(Ư\left(3\right)=\left\{\pm1;\pm3\right\}\)
\(\Rightarrow\left\{{}\begin{matrix}x=1\\y-1=3\Rightarrow y=4\\x=-1\\y-1=-3\Rightarrow y=-4\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x=3\\y-1=1\Rightarrow y=2\\x=-3\\y-1=-1\Rightarrow y=0\end{matrix}\right.\)
=>x(y-1) = 3 hay x; (y-1) là các ước của 3
Mà Ư(3) = 1;-1;3;-3
\(=>\left[{}\begin{matrix}x=1\\x=-1\\x=3\\x=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}y=4\\y=-4\\y=2\\y=0\end{matrix}\right.\)
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