Đáp án + giải thích các bước giải:

`a, 7/-25 + -18/25 + 4/23 + 5/7 + 19/23`

`= (-7/25 + -18/25) + (4/23 + 19/23) + 5/7`

`= -25/25 + 23/23 + 5/7`

`= -1 + 1 + 5/7`

`= 5/7`

`b, 7/19 . 8/11 + 7/19 . 3/11 + 12/19`

`= 7/19 .(8/11 + 3/11) + 12/19`

`= 7/19 . 11/11 + 12/19`

`= 7/19 + 12/19`

`= 19/19 = 1`

`c, (-25).125.4.(-8).(-17)`

`= [(-25).4][125.(-8)](-17)`

`= (-100)(-1000)(-17)`

`= -1700000`

`d, 7/35 . 10/19 + 7/35.9/19 - 2/35`

`= 7/35 .(10/19 + 9/19) - 2/35`

`= 7/35 . 19/19 - 2/35`

`= 7/35 - 2/35`

`= 5/35 = 1/7`