Question

tìm x

7⋮ (3x + 1 )

Answer 1

`7 \vdots (3x+1)`

   `=>3x+1 in Ư_7`

Mà `Ư_7={+-1;+-7}`

`@3x+1=1=>x=0`

`@3x+1=-1=>x=-2/3`

`@3x+1=7=>x=2`

`@3x+1=-7=>x=-8/3`