Question

  Giải nhanh hộ

Answer 1

`@` `\text {Ans}`

`\downarrow`

`a)`

`-4/7 - 12/21 + 1/7`

`= -8/7 + 1/7`

`= -1`

`b)`

`2,5 - (-1)/2 + 3/4`

`=3 + 3/4`

`= 15/4`