`a ) x - 1/5 = 6/15`

`x = 6/15 + 1/5`

`x = 6/15 + 3/15`

`x = 3/5`

Vậy `x = 3/5`

`b ) x - 5/6 = 7/8`

`x = 7/8 + 5/6`

`x = 41/24`

Vậy `x = 41/24`

`c ) 4/5 - x = 1/10`

`x = 4/5 - 1/10`

`x = 7/10`

Vậy `x = 7/10`

------

`4/5 = x - 1/10`

`x = 1/10 + 4/5`

`x = 9/10`

Vậy `x = 9/10`

Tính :

`a ) 1/12 - 5/8 + 4/6`

`= -13/24 + 4/6`

`= 1/8`

`b ) 3/11 - ( 4/5 - 8/11 ) + 4/5`

`= 3/11 - 4/5 + 8/11 + 4/5`

`= ( 3/11 + 8/11 ) - ( 4/5 - 4/5 )`

`= 1`

`color{red}{Fenik}`