Đáp án:
c, `5/23` c, `(-5)/11` c, `24/35`
Giải thích các bước giải:
c, `5/7` . `19/23` - `12/23` . `5/7`
= `5/7` . (`19/23` - `12/23`)
= `5/7` . `7/23`
= `5/23`
c, `(-10)/11` . `8/9` + `7/18` . `10/11`
= `10/11` . `(-8)/9` + `7/18` . `10/11`
= `10/11` . ( `(-8)/9` + `7/18` )
= `10/11` . `(-1)/2`
= `(-5)/11`
c, `12/25` . `23/7` - `12/7` . `13/25`
= `12/7` . `23/25` - `12/7` . `13/25`
= `12/7` . (`23/25` - `13/25`)
= `12/7` . `10/25`
= `24/35`
Chúc bạn học tốt !