Giải thích các bước giải:

`|-5/14| - x : 6/11 = -3/7`

`5/14 - x : 6/11 = -3/7`

`x : 6/11 = 5/14 - (-3)/7`

`x : 6/11 = 5/14 + 6/14`

`x : 6/11 = 11/14`

`x = 11/14 . 6/11`

`x = 3/7`

Vậy, `x = 3/7`

`-----`

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

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

`x - 1/2 = 49/4`

`x = 49/4 + 1/2`

`x = 49/4 + 2/4`

`x = 51/4`

Vậy, `x = 51/4`

`-----`

`1/3x + 2/5 ( x - 1 ) = 0`

`1/3x + 2/5x - 2/5 = 0`

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

`( 5/15 + 6/15 )x = 2/5`

`11/15x = 2/5`

`x = 2/5 : 11/15`

`x = 6/11`

Vậy, `x = 6/11`

`#tm`