\(6⋮\left(x-1\right)\)
\(\Rightarrow x-1\in\text{ư}\left(6\right)=1.2.3.6\)
\(\Rightarrow x-1=1\)
\(\Rightarrow x-1=2\)
\(\Rightarrow x-1=3\)
\(\Rightarrow x-1=6\)
\(x=1+1=2\)
\(x=1+2=3\)
\(x=1+3=4\)
\(x=1+6=7\)
=> x - 1 \(\in U\left[6\right]\in\left\{-6;-3;-2;-1;1;2;3;6\right\}\)
\(\Rightarrow x\in\left\{-5;-2;-1;0;2;3;4;7\right\}\)
x - 1 thuộc Ư { 6 } = { -6 ; -3 ; -2 ; -1 ; 1 ; 2 ; 3 ; 6 }
Suy ra x thuộc { -5 ; -2 ; -1 ; 0 ; 1 ; 2 ; 3 ; 4 ; 7 }