Question

3n+8 chia hết cho 2n+3

Answer 1

`3n+8` chia hết cho `2n+3`

`=>2(3n+8)` chia hết cho `2n+3`

`=>6n+16` chia hết cho `2n+3`

`=>(6n+9)+7` chia hết cho `2n+3`

`=>3(2n+3)+7` chia hết cho `2n+3`

`=>7` chia hết cho `2n+3`

`=>2n+3∈Ư(7)={1;-1;7;-7}`

`=>2n∈{-2;-4;4;-10}`

`=>n∈{-1;-2;2;-5}` 

Answer 2