tìm số nguyên x sao cho : 4x + 3 chia hết cho x - 2

2 câu trả lời

Đáp án:

`4x + 3 \vdots x - 2`

`↔ 4x - 8 + 11 \vdots x - 2`

`↔ 4.(x - 2) + 11 \vdots x - 2`

`↔ 11 \vdots x - 2`

`↔ x - 2 ∈ Ư_{(11)} = {1;-1;11;-11}`

`↔ x ∈ {3;1; 13; -9}`

Vậy `x ∈ {3;1; 13; -9}`

$#dariana$

`4x+3\vdotsx-2`

`<=>4x-8+11vdotsx-2`

`<=>4(x-2)+11\vdotsx-2`

`<=>11\vdotsx-2`

`<=>x-2\inƯ(11)={-1;1;-11;11}`

`->x-2=1->x=3`

`->x-2=-1->x=1`

`->x-2=11->x=13`

`->x-2=-11->x=-9`

Vậy `x\in{3;1;13;-9}`