Tìm N ∈ Z, sao cho: n ÷2016 chia hết n ÷2019 30/09/2021 Bởi Hadley Tìm N ∈ Z, sao cho: n ÷2016 chia hết n ÷2019
Đáp án + giải thích bước giải : `n – 2016 \vdots n – 2019` `-> n – 2016 + 3 \vdots n – 2019` `-> 3 \vdots n – 2019` `-> n – 2019 ∈ Ư (3) = {±1; ±3} (n ∈ Z)` `-> n – 2019 = 1 -> n = 2020` `-> n – 2019 = -1 -> n = 2018` `-> n – 2019 = 3 -> n = 2022` `-> n – 2019 = -3 -> n = 2016` Vậy `n ∈ {2020; 2018; 2022; 2016}` thì `n – 2016 \vdots n – 2019` Bình luận
Đáp án: `n-2016 \ vdots \ n-2019` `=> n-2019+3 \ vdots \ n-2019` `=> 3 \ vdots \ n-2019` `=> n-2019 in Ư(3)={-3;-1;1;3}` `=> n in {2016;2018;2020;2022}` Bình luận
Đáp án + giải thích bước giải :
`n – 2016 \vdots n – 2019`
`-> n – 2016 + 3 \vdots n – 2019`
`-> 3 \vdots n – 2019`
`-> n – 2019 ∈ Ư (3) = {±1; ±3} (n ∈ Z)`
`-> n – 2019 = 1 -> n = 2020`
`-> n – 2019 = -1 -> n = 2018`
`-> n – 2019 = 3 -> n = 2022`
`-> n – 2019 = -3 -> n = 2016`
Vậy `n ∈ {2020; 2018; 2022; 2016}` thì `n – 2016 \vdots n – 2019`
Đáp án:
`n-2016 \ vdots \ n-2019`
`=> n-2019+3 \ vdots \ n-2019`
`=> 3 \ vdots \ n-2019`
`=> n-2019 in Ư(3)={-3;-1;1;3}`
`=> n in {2016;2018;2020;2022}`