Làm hộ tôi bài 2 vs mọi người ơi

`a)` `4/5 ×2/7 + 4/5 × 5/7`

`=` `4/5 × (2/7 +5/7)`

`=` `4/5 × 1` 

`=` `4/5`

`b)` `9/5 ×7/3 + 9/5 × 9/3 - 9/5 × 13/3`

`=` `9/5 × ( 7/3 + 9/3 -13/3)`

`=`` 9/5 × 1 `

`=` `9/5`

c) `-4/5 × 10/3 +` $\dfrac{-4}{5}$ `×5/3`

`=` `-4/5 × (10/3 + 5/3)`

`=` `-4/5 × 3 `

`=` `-12/3`

`=` `-4`

`d)` `-5/4 × 1/2 + `$\dfrac{-5}{4}$` ×` $\dfrac{-3}{2}$ `-1/4`

`=` `-5/4 × (1/2 +` $\dfrac{-3}{2}$`) -1/4`

`=` `-5/4 × (-1) -1/4`

`=` `5/4 - 1/4 `

`=` `1`