4x-12 chia hết x-1

Ai giúp em với ạ

`4x-12vdotsx-1`

`=>4x-4-8vdotsx-1`

`=>4(x-1)-8vdotsx-1`

Vì `4(x-1)vdotsx-1`

`=>8vdotsx-1`

`=>x-1 in Ư(8)={+-1;+-2;+-4;+-8}`

Ta có bảng sau:

\begin{array}{|c|c|c|}\hline \text{$x-1$}&\text{1}&\text{$-1$}&\text{2}&\text{$-2$}&\text{4}&\text{$-4$}&\text{8}&\text{$-8$}\\\hline \text{$x$}&\text{2}&\text{0}&\text{3}&\text{$-1$}&\text{5}&\text{$-3$}&\text{9}&\text{$-7$}\\\hline\end{array}

Vậy `x in {-7;-3;-1;0;2;3;5;9}`