Đáp án:
tham khảo
Giải thích các bước giải:
`a//` `1(4)/13+15/22+9/13+7/22-2`
`=(1(4)/13+9/13)+(15/22+7/22)-2`
`=2+1-2`
`=1`
$\\$
`b//` `(-3)/7 . 15/23 + (-3)/23 . 8/7 + 9/21`
`=(-3)/7 . 15/23 + (-3)/7 . 8/23 + 9/21`
`=(-3)/7 . (15/23+8/23)+9/21`
`=(-3)/7 +9/21`
`=0`
$\\$
`c//` `4(7)/12-(11(1)/24+5(7)/12)`
`=4(7)/12-11(1)/24-5(7)/12`
`=(4(7)/12-5(7)/12)-11(1)/24`
`=-1-11(1)/24`
`=-12(1)/24`
$\\$
`d//` `3/7÷21/4-3/7÷13/4`
`=3/7 . 4/21 - 3/7 . 4/13`
`=3/7 . ( 4/21 - 4/13 ) `
`=3/7 . (-32)/273`
`=(-32)/637`
