giải giúp mình 8 câu trên

Đáp án `+` Giải thích các bước giải:

11.

a) `-13/15 + x = -3/8 - (-4)/5`

`-13/15 + x = -15/40 + 32/40`

`-13/15 + x = 17/40`

`x = 17/40 - (-13)/15`

`x = 51/120 + 104/120`

`x = 155/120`

`x = 31/24.`

b) `3/7 + x = 1/4 - (-3/5)`

`3/7 + x = 5/20 + 12/20`

`3/7 + x = 17/20`

`x = 17/20 - 3/7`

`x = 119/140 - 60/140`

`x = 59/140.`

c) `1/20 - (x - 8/5) = 1/10`

`x - 8/5 = 1/20 - 1/10`

`x - 8/5 = 1/20 - 2/20`

`x - 8/5 = -1/20`

`x = -1/20 + 8/5`

`x = -1/20 + 32/20`

`x = 31/20.`

d) `1/10 - (x - 3/25) = 1/50`

`x - 3/25 = 1/10 - 1/50`

`x - 3/25 = 5/50 - 1/50`

`x - 3/25 = 4/50`

`x - 3/25 = 2/25`

`x = 2/25 + 3/25`

`x = 5/25`

`x = 1/5.`

12.

a) `-3/11 - (x - 2/5) = -14/22`

`-3/11 - (x - 2/5) = -7/11`

`x - 2/5 = -3/11 - (-7)/11`

`x - 2/5 = 4/11`

`x = 4/11 + 2/5`

`x = 20/55 + 22/55`

`x = 42/55.`

b) `-7/13 - (x - 4/3) = -17/26`

`x - 4/3 = -7/13 - (-17)/26`

`x - 4/3 = -14/26 + 17/26`

`x - 4/3 = 3/26`

`x = 3/26 + 4/3`

`x = 9/78 + 104/78`

`x = 113/78.`

c) `11/12 - (2/5 + x) = 2/3`

`2/5 + x = 11/12 - 2/3`

`2/5 + x = 11/12 - 8/12`

`2/5 + x = 3/12`

`2/5 + x = 1/4`

`x = 1/4 - 2/5`

`x = 5/20 - 8/20`

`x = -3/20.`

d) `11/16 - (x - 7/3) = 2/4`

`x - 7/3 = 11/16 - 2/4`

`x - 7/3 = 11/16 - 8/16`

`x - 7/3 = 3/16`

`x = 3/16 + 7/3`

`x = 9/48 + 112/48`

`x = 121/48.`