Đáp án:
Giải thích các bước giải:
`a,6x+3 \vdots x`
Mà `6x \vdots x`
`\to 3 \vdots x`
`\to x∈Ư(3)`
`\to x∈{1,-1,3,-3}`
Vậy `x∈{1,-1,3,-3}`
,
`b,4x+4 \vdots 2x-1`
`\to 4x-2+6 \vdots 2x-1`
`\to 2(2x-1)+6 \vdots 2x-1`
Mà `2(2x-1) \vdots 2x-1`
`\to 6 \vdots 2x-1`
`\to 2x-1∈Ư(6)`
`\to 2x-1∈{1,-1,2,-2,3,-3,6,-6}`
`\to 2x∈{2,0,3,-1,4,-2,7,-5}`
`\to x∈{1,0,2,-1}`
Vậy `x∈{1,0,2,-1}`
,
`c,x²-9x+7 \vdots x-9`
`\to x(x-9)+7\vdots x-9`
Mà `x(x-9) \vdots x-9`
`\to 7 \vdots x-9`
`\to x-9∈Ư(7)`
`\to x-9∈{-1,1,7,-7}`
`\to x∈{8,10,16,2}`
Vậy `x∈{8,10,16,2}`
