a, -8/15 + 7/9 – 11/12 b, -1/2 × 4/9 + 3/7 × 15/14 c, 8 và 2/7 – ( 2 và 4/9 + 4 và 2/7) 06/08/2021 Bởi Emery a, -8/15 + 7/9 – 11/12 b, -1/2 × 4/9 + 3/7 × 15/14 c, 8 và 2/7 – ( 2 và 4/9 + 4 và 2/7)
Đáp án: `a, -8/15 + 7/9 – 11/12` `= 11/45 – 11/12` `= -121/180` `b, -1/2 × 4/9 + 3/7 × 15/14` `= -2/9 + 45/98` `= 209/882` `c, 8 2/7 – (2 4/9 + 4 2/7)` `= 58/7 – 22/9 – 30/7` `= (58/7 – 30/7) – 22/9` `= 4 – 22/9` `= 14/9` Bình luận
@ Đạt em Đáp án + Cách làm : a) `-8/15` + `7/9` – `11/12` = ( `-8/15` + `7/9` ) – `11/12` = `11/45` – `11/12` = `-121/180` b) `-1/2` × `4/9` + `3/7` × `15/14` = ( `-1/2` × `4/9` ) + ( `3/7` × `15/14` ) = `-2/9` + `45/98` = `209/882` c) 8 `2/7` -( 2 `4/9` + 4 `2/7` ) = 8 `2/7` – 2 `4/9` – 4 `2/7` = (8 `2/7` – 4 `2/7` ) – 2 `4/9` = ( `58/7` – `30/7` ) – `22/9` = `28/7` – `22/9` = 4 – `22/9` = `36/9` – `22/9` = `14/9` Bình luận
Đáp án:
`a, -8/15 + 7/9 – 11/12`
`= 11/45 – 11/12`
`= -121/180`
`b, -1/2 × 4/9 + 3/7 × 15/14`
`= -2/9 + 45/98`
`= 209/882`
`c, 8 2/7 – (2 4/9 + 4 2/7)`
`= 58/7 – 22/9 – 30/7`
`= (58/7 – 30/7) – 22/9`
`= 4 – 22/9`
`= 14/9`
@ Đạt em
Đáp án + Cách làm :
a) `-8/15` + `7/9` – `11/12`
= ( `-8/15` + `7/9` ) – `11/12`
= `11/45` – `11/12`
= `-121/180`
b) `-1/2` × `4/9` + `3/7` × `15/14`
= ( `-1/2` × `4/9` ) + ( `3/7` × `15/14` )
= `-2/9` + `45/98`
= `209/882`
c) 8 `2/7` -( 2 `4/9` + 4 `2/7` )
= 8 `2/7` – 2 `4/9` – 4 `2/7`
= (8 `2/7` – 4 `2/7` ) – 2 `4/9`
= ( `58/7` – `30/7` ) – `22/9`
= `28/7` – `22/9`
= 4 – `22/9`
= `36/9` – `22/9`
= `14/9`