Question

tìm x: x +5 chia hết x- 2

Answer 1

`x+5 vdots x-2`

`=>x-2+7 vdots x-2`

`=>7 vdots x-2`

`=>x-2 in Ư(7)={+-1,+-7}`

`=>x in {1,3,9,-5}`

Answer 2

a)Để A là số nguyên thì x+5⋮x-2

x+7-2⋮x-2

x-2⋮x-2⇒7⋮x-2

x-2∈Ư(7)

Ư(7)={1;-1;7;-7}

Vậy n ∈ {3;1;9;-5}

Answer 3

Ta có: \(x+5⋮x-2\)

nên \(7⋮x-2\)

\(\Leftrightarrow x-2\in\left\{1;-1;7;-7\right\}\)

hay \(x\in\left\{3;1;9;-5\right\}\)