Bài 1 thực hiện phép tính

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

2) -(3/7+3/8)-(-3/8+4/7)

3) (-25/7-31/42)-(-7/27-3/42)

4) (-1/2+7/6)-(-5/2+1/6)

5) (16/21+27/12)-(14/12-5/21)

6) (13/23+(-15/4)+(10/23-1/4)

`color{Cyan}{#317}`

Đáp án `+` Lời Giải :

`1)- ( 3/5  +  3/4 )  -  (  -3/4  + 2/5  )`
`= -3/5   -  3/4    +  3/4  -  2/5`
`= -27/20+7/20`
`=-1`

`2) -(3/7+3/8)-(-3/8+4/7)`

`=-3/7-3/8+3/8-4/7`

`=(-3/7-4/7)+(-3/8+3/8)`

`=-1+1=0`

`3) (-25/27 - 31/42) - (-7/27 - 3/42)`

`=-25/27-31/42+7/27+3/42`

`=(-25/27+7/27)-(31/42-3/42)`

`=(-18/27)-28/42`

`=(-2/3)-2/3`

`=-4/3`