\(6⋮n-1\)
Ta có : Ư(6)={\(\pm1;\pm2;\pm3;\pm6\)}
nếu n-1=1 thì n=2
nếu n-1=-1 thì n=0
nếu n-1=2 thì n=3
nếu n-1=-2 thì n=-1
nếu n-1=3 thì n=4
nếu n-1=-3 thì n=-2
nếu n-1=6 thì n=7
nếu n-1=-6 thì n=-5
Vậy \(n\in\left\{2;0;-1;4;-2;7;-5\right\}\)
N-1\(\inƯ\left(6\right)\)
\(N-1\in\left\{\pm1,\pm2,\pm3,\pm6\right\}\)
\(N\in\left\{-5;-2;-1-0;2;3;4;7\right\}\)