Đáp án:
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Giải thích các bước giải:
Câu 1:
`BC [ 5,13,17,25 ]`
Ta có: `5 = 5`
`13= 13`
`17=17`
`25 = 5^2 `
`⇒BCNN {5,13,17,25}= 1 `
`BC { 5,13,17,25} = 1`
Vậy `BC { 5 , 13,17,25 }=1`
Câu 2:
`a)`
`n-2 ` `\vdots` ` n`
`b)`
`3n+1 ` `\vdots` ` n+1`
`c)`
`2n+1` `\vdots` ` 2n`
`b)`
`3n+1 ` `\vdots` `n+1`
`⇒[3n+1]-[n+1]` `\vdots` `n+1`
`3n+1-n+1` `\vdots` `n+1 `
`0` `\vdots` `n+1`
`c)`
`2n+1 ` `\vdots` ` 2n`
`⇒2n+1-n+1` `\vdots` `2n `
`2n+1-n+1` `\vdots` `2n `
`0 ` `\vdots` `n+1 `