\(2x-xy-3y+1=0\)
\(\Rightarrow2x-xy-3y+1+5=5\)
\(\Rightarrow2x-xy-3y+6=5\)
\(\Rightarrow x\left(2-y\right)+3\left(2-y\right)=5\)
\(\Rightarrow\left(x+3\right)\left(2-y\right)=5\)
\(\Rightarrow x+3;2-y\inƯ\left(5\right)\)
\(Ư\left(5\right)=\left\{\pm1;\pm5\right\}\)
\(\Rightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x+3=1\Rightarrow x=-2\\2-y=5\Rightarrow y=-3\end{matrix}\right.\\\left\{{}\begin{matrix}x+3=-1\Rightarrow x=-4\\2-y=-5\Rightarrow y=7\end{matrix}\right.\\\left\{{}\begin{matrix}x+3=5\Rightarrow x=2\\2-y=1\Rightarrow y=1\end{matrix}\right.\\\left\{{}\begin{matrix}x+3=-5\Rightarrow x=-8\\2-y=-1\Rightarrow y=3\end{matrix}\right.\end{matrix}\right.\)
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