`b) (-6)/17 . (-2021)/2022 + 2021/2022 .(-23)/17 + 2021/2022`
`=2021/2022 .(6/17 + (-23)/17 + 1)`
`=2021/2022.0`
`=0`
b) -6/17 . -2021/2022 + 2021/2022 . -23/17 + 2021/2022
= 6/17 . 2021/2022 + 2021/2022 . -23/17 + 17/17 . 2021/2022
= (-23+6+17)/17 . 2021/2022
= 0/17 . 2021/2022
= 0 . 2021/2022 = 0