Giúp với ạ hu hu hu hu hu hu cứu tui ik cho 5seo a

`a)3/(7).(9)/26-1/(14).(1)/13-1/7`

`=27/182-(1/182+26/182)`

`=27/182-27/182=0`

`b)(-5)/(6).(4)/19+(-7)/(12).(4)/19-40/57`

`=4/19(-5/6-7/12)-40/57`

`=4/19.(-17)/12-40/57`

`=-17/57-40/57=-67/57`