+ `(x-1) \vdots 5`
`→(x-1)∈Ư(5)`
`→(x-1)∈{1;-1;5;-5}`
Xét bảng: (ảnh 1)
Vậy `x∈{2;0;6;-4}`
+ `(x-1)²=81`
\(→\left\{{\matrix{{x-1=9} \cr{x-1=-9} \cr}}\right.\)
\(→\left\{{\matrix{{x=0} \cr{x=-8} \cr}}\right.\)
+ `2.(x-3)-3.(x-5)=4.(3-x)-18`
`→2x-6-3x+15=12-4x-18`
`→2x-3x+4x=12-18+6-15`
`→3x=-15`
`→x=-5`
+ `-2x-11 \vdots 3x+2`
`→-3(-2x-11) \vdots 3x+2`
`→6x+33 \vdots 3x+2`
`→(6x+4)+29 \vdots 3x+2`
`→2(3x+2)+29 \vdots 3x+2`
`→29 \vdots 3x+2`
`→3x+2 ∈ {-1;1;-29;29}`
Xét bảng: (ảnh 2)
Vậy `x∈{-1; -1/3; 9; (-31)/3}`
