Giúp emmmmmmmm với ạ 5 sao nhanhhh lẹ ạ

`a.`

`31/17+(-5)/13+(-8)/13-14/17`

`=(31/17-14/17)+((-5)/13+(-8)/13)`

`=17/17+(-13)/13`

`=1+(-1)`

`=0`

`b.`

`34/19+(-7)/15+(-8)/15-15/19`

`=(34/19-15/19)+((-7)/15+(-8)/15)`

`=19/19+(-15)/15`

`=1+(-1)`

`=0`