Đáp án:

 

Giải thích các bước giải:

`x - 1/5 = 2/11`

`=>x = 2/11 + 1/5`

`=>x = 10/55 + 11/55`

`=>x = 21/55`

Vậy `x = 21/55`

`---`

`x - 5/6 = 16/42 + (-8/56)`

`=>x - 5/6 = 8/21 - 1/7`

`=>x - 5/6 = 8/21 - 3/21`

`=>x - 5/6 =5/21`

`=>x = 5/21 + 5/6`

`=>x = 10/42 + 35/42`

`=>x = 15/14`

Vậy `x = 15/14`

`---`

`x/5 = 5/6 + (-19/30)`

`=>x/5 = 25/30 - 19/30`

`=>x/5 = 1/5`

`=>x = 1`

Vậy `x = 1`

`---`

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

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

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

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

`=>x = 21/14 - 2/14`

`=>x = 19/14`

Vậy `x = 19/14`

`~nhungan~`