Toán Tính hợp lý: M= 2/3+9/10-11/15+13/21-15/28+17/36-19/45+21/55-23/66 08/09/2021 By Eva Tính hợp lý: M= 2/3+9/10-11/15+13/21-15/28+17/36-19/45+21/55-23/66
*Lời giải : `M = 2/3 + 9/10 – 11/15 + 13/21 – 15/28 + 17/36 – 19/45 + 21/55 – 23/66` `⇔ M = 2/3 + (9/10 – 11/15) + (13/21 – 15/28) + (17/36 – 19/45) + (21/55 – 23/66)` `⇔ M = 2/3 + 1/6 + 1/12 + 1/20 + 1/30` `⇔ M = 2/3 + (1/6 + 1/2 + 1/20 + 1/30)` `⇔ M = 2/3 + 1/3` `⇔ M = 1` Vậy `M = 1` Trả lời
Đáp án: `M=1` Giải thích các bước giải: `M= 2/3+9/10-11/15+13/21-15/28+17/36-19/45+21/55-23/66` `=>M=2/3+[(9/10-11/15)+(13/21-15/28)+(17/36-19/45)+(21/55-23/66)]` `=>M=2/3+[1/6+1/12+1/20+1/30]` `=>M=2/3+1/3` `=>M=3/3=1` Trả lời
*Lời giải :
`M = 2/3 + 9/10 – 11/15 + 13/21 – 15/28 + 17/36 – 19/45 + 21/55 – 23/66`
`⇔ M = 2/3 + (9/10 – 11/15) + (13/21 – 15/28) + (17/36 – 19/45) + (21/55 – 23/66)`
`⇔ M = 2/3 + 1/6 + 1/12 + 1/20 + 1/30`
`⇔ M = 2/3 + (1/6 + 1/2 + 1/20 + 1/30)`
`⇔ M = 2/3 + 1/3`
`⇔ M = 1`
Vậy `M = 1`
Đáp án:
`M=1`
Giải thích các bước giải:
`M= 2/3+9/10-11/15+13/21-15/28+17/36-19/45+21/55-23/66`
`=>M=2/3+[(9/10-11/15)+(13/21-15/28)+(17/36-19/45)+(21/55-23/66)]`
`=>M=2/3+[1/6+1/12+1/20+1/30]`
`=>M=2/3+1/3`
`=>M=3/3=1`