TTính biểu thức sau một cách hợp líA=7/19 .8/11 7/19.3/11 12/19 B=5/9.7/13+5/9.9/13-5/9.3/13 23/10/2021 Bởi Ivy TTính biểu thức sau một cách hợp líA=7/19 .8/11 7/19.3/11 12/19 B=5/9.7/13+5/9.9/13-5/9.3/13
`A=7/19 . 8/11+7/19 . 3/11+12/19` `⇒A=7/19.(8/11+3/11)+12/19` `⇒A=7/19 . 11/11+12/19` `⇒A=7/19 . 1+12/19` `⇒A=7/19 +12/19` `⇒A=19/19 ` `⇒A=1 ` `B=5/9 . 7/13+5/9 . 9/13-5/9 . 3/13` `⇒B=5/9.(7/13+9/13-3/13)` `⇒B=5/9 . 13/13` `⇒B=5/9 . 1` `⇒B=5/9 ` Bình luận
`A=7/19 . 8/11+7/19 . 3/11+12/19`
`⇒A=7/19.(8/11+3/11)+12/19`
`⇒A=7/19 . 11/11+12/19`
`⇒A=7/19 . 1+12/19`
`⇒A=7/19 +12/19`
`⇒A=19/19 `
`⇒A=1 `
`B=5/9 . 7/13+5/9 . 9/13-5/9 . 3/13`
`⇒B=5/9.(7/13+9/13-3/13)`
`⇒B=5/9 . 13/13`
`⇒B=5/9 . 1`
`⇒B=5/9 `