\(6⋮n+2\)
\(\Rightarrow n+2\inƯ\left(6\right)\)
\(Ư\left(6\right)=\left\{\pm1;\pm2;\pm3;\pm6\right\}\)
\(\Rightarrow n\in\left\{-3;-1;0;-4;1;-5;4;-8\right\}\)
\(n-3⋮n+1\)
\(\Rightarrow n+1-4⋮n+1\)
\(\Rightarrow4⋮n+1\)
Xét ước như trên
\(3n+7⋮n-1\)
\(\Rightarrow3n-3+10⋮n-1\)
\(\Rightarrow3\left(n-1\right)+10⋮n-1\)
\(10⋮n-1\)
Xét ước như trên