Làm nhanh lên mọi người ơi

`20)`

`2x-2/3-7x=3/2-1`

`=>2x-7x=3/2-1+2/3`

`=>-5x=1/2+2/3`

`=>-5x=2=3/6+4/6`

`=>-5x=7/6`

`=>x=7/6:(-5)`

`=>x=-7/30`

Vậy `x=-7/30`

`23)`

`2x-1/4=5/6-1/2x`

`=>2x+1/2x=5/6+1/4`

`=>5/2x=10/12+3/12`

`=>5/2x=13/12`

`=>x=13/12:5/2`

`=>x=13/30`

Vậy `x=13/30`

`29)`

`3.(x-1/2)-3.(x-1/3)=x`

`=>3.(x-1/2-x+1/3)=x`

`=>x=3.(-1/2+1/3)`

`=>x=3.(-3/6+2/6)`

`=>x=3.(-1)/6`

`=>x=-1/2`

Vậy `x=-1/2`