giải chi tiết nha....

Đáp án:

Giải thích các bước giải:

` 3) F = 15/14 - ( 17/23 - 80/87 + 5/4 ) + ( 17/23 - 15/14 + 1/4 ) `

` F = 15/14 - 17/23 + 80/87 - 5/4 + 17/23 - 15/14 + 1/4 `

` F = 80/87 + ( 15/14 - 15/14 ) + ( 17/23 - 17/23 ) - ( 5/4 - 1/4 ) `

` F = 80/87 + 0 + 0 - 1 `

` F = 80/87 - 1 `

` F = 80/87 - 87/87 `

` F = -7/87`

` 4) G = 1/25 - 4/27 + ( -23/27 + (-1)/25 - 5/43 ) + 5/43 - 4/7 `

` G = 1/25 - 4/27 - 23/27 - 1/25 - 5/43 + 5/43 - 4/7 `

` G = ( 1/25 - 1/25 ) - ( 4/27 + 23/27 ) + ( 5/43 - 5/43 ) - 4/7 `

` G = 0 - 1 + 0 - 4/7 `

` G = -1 - 4/7 `

` G = -7/7 - 4/7 `

` G = -11/7 `

` color{blue}{@75} `