Đáp án:
`a)-1`
`b)4`
Giải thích các bước giải:
`a)(4/19-5/113)-(4/19+108/113)`
`=4/19-5/113-4/19-108/113`
`=(4/19-4/19)-(5/113+108/113)`
`=0-113/113`
`=-113/113`
`=-1`
`b)(2(5)/6-0,7+3(1)/40)-(17/6-7/10-39/40)`
`=(17/6-7/10+121/40)-(17/6-7/10-39/40)`
`=17/6-7/10+121/40-17/6+7/10+39/40`
`=(17/6-17/6)+(-7/10+7/10)+(121/40+39/40)`
`=0+0+160/40`
`=160/40`
`=4`