giúp e với, e cảm ơn ạa

a, `2/7 + 3/5 . 5/7 - 4/7`

`= 2/7 + 3/7 - 4/7`

`= (2 + 3 - 4)/7`

`= 1/7`

b, `5/36 + (-7)/9 - 15/8 : 3/2`

`= 5/36 + (-7)/9 - 15/8 . 2/3`

`= 5/36 + (-7)/9 - 15/12`

`= 5/36 + (-28)/36 - 45/36`

`= (5 + (-28) - 45)/36`

`= (-17)/9`

d, `(3/4 + 2/3) : 17/24 - 3/4`

`= (9/12 + 8/12) . 24/17 - 3/4`

`= 17/12 . 24/17 - 3/4`

`= 2 - 3/4`

`= 8/4 - 3/4`

`= 5/4`

e, `1/7 + 6/7 . (1/2 - 1/3)`

`= 1/7 + 6/7 . (3/6 - 2/6)`

`= 1/7 + 6/7 . 1/6`

`= 1/7 + 1/7`

`= 2/7`