Do `3x-2 vdots 2x+1`
`=> 6x-4 vdots 2x+1`
Do `2x+1 vdots 2x+1`
`=> 6x + 3 vdots 2x+1`
`=> 6x + 3 - (6x-4) vdots 2x+1`
`=> 6x + 3 - 6x + 4 vdots 2x+1`
`=> 7 vdots 2x+1`
`=> 2x + 1 ∈ Ư(7) = {1;-1;7;-7}`
`=> 2x ∈ {0;-2;6;-8}`
`=> x ∈ {0;-1;3;-4}`
(Chúc bạn học tốt ạ)