\(2n+5⋮n-1\)
Mà \(n-1⋮n-1\)
\(\Leftrightarrow\left\{{}\begin{matrix}2n+5⋮n-1\\2n-2⋮n-1\end{matrix}\right.\)
\(\Leftrightarrow7⋮n-1\)
\(\Leftrightarrow n-1\inƯ\left(7\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}n-1=1\-1=7\-1=-1\-1=-7\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}n=2\=8\=0\=-6\end{matrix}\right.\)
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