Đáp án:
Giải thích các bước giải:
`9)`
`2/5. (-8)/19 -11/19 . 2/5 +(-1)^2021`
`=2/5 .((-8)/19 -11/19) +(-1)`
`=2/5 . (-1)-1`
`=-2/5-1`
`=-7/5`
`10)`
`1 10/15.(0,2)^2+(8/15-1 16/30)`
`=25/15 . 1/ 25 +8/15 - 46/30`
`=1/15 +8/15 - 23/15`
`=-14/15`
`11)`
`(-6)/23 :29/12 +6/23 :29/41`
`=6/23 :(-29)/12 +6/23 :29/41`
`=6/23 . (-12)/29 +6/23 . 41/29`
`=6/23 . ((-12)/29 +41/29)`
`=6/23 .1`
`=6/23`
`12)`
`-2,5:|1+2/3|`
`=-2,5:|5/3|`
`=-2,5 : 5/3`
`=-3/2`
