Bài 2. (2,0 điểm) Tìm x, biết: a) $\frac{2}{5}$+ x = $\frac{-1}{2}$  b) $2: \frac{11}{5}$ - ($\frac{1}{3}$ - $\frac{1}{11}$ ) c)  $\frac{x-2}{3}$ = $\frac{2x+1}{5}$ 

Bài `2:`

`a)` `2/5 + x = -1/2`

`=>` `x = (-1/2) - 2/5`

`=>` `x=  -9/10`

Vậy `x = -9/10`

`b)` `(7/6 - 3x) . (-1)/3 = 1/4`

`=>` `7/6 - 3x= 1/4 : (-1)/3`

`=>` `7/6 - 3x = -3/4`

`=>` `3x = 7/6 - 3/4`

`=>` `3x = 5/12`

`=>` `x=5/12 : 3`

`=>` `x = 5/36`

Vậy `x = 5/36`

`c)` `(x -2)/3 = (2x +1)/=5`

`=> 5.(x -2) = 3.(2x +1)`

`=> 5x - 10 = 6x + 3`

`=> 5x - 6x = 3 + 10`

`=> -x = 13`

`=> x= -13`

Vậy `x = -13`