Đáp án + Giải thích các bước giải:
`a//`
`-(3)/(x-1)∈ZZ`
`=>3\vdots x-1`
`=>x-1∈Ư(3)={±1;±3}`
`=>x∈{0;-2;2;4}`
`b//`
`-(4)/(2x-1)∈ZZ`
`=>4\vdots 2x-1`
`=>2x-1∈Ư(4)={±1;±2;±4}`
`=>2x-1∈{±1}` . Vì `2x-1` là số lẻ `(∀x∈ZZ)`
`=>2x∈{0;2}`
`=>x∈{0;1}`
`c//`
`(3x+7)/(x-1)∈ZZ`
`=>3x+7\vdots x-1`
`=>3(x-1)+10\vdots x-1`
Vì `3(x-1)\vdots x-1`
`=>10\vdots x-1`
`=>x-1∈Ư(10)={±1;±2;±5;±10}`
`=>x∈{0;-1;-4;-9;2;3;6;11}`
`d//`
`(4x-1)/(3-x)∈ZZ`
`=>4x-1\vdots 3-x`
`=>-4(3-x)+11\vdots 3-x`
Vì `-4(3-x)\vdots 3-x`
`=>11\vdots 3-x`
`=>3-x∈Ư(11)={±1;±11}`
`=>x∈{2;-8;4;14}`
