![](https://rs.olm.vn/images/background/bg124356916738.jpg?v=2?)
![](https://rs.olm.vn/images/avt/2.png?13)
phạm văn nhất
Giới thiệu về bản thân
Mình sợ bạn quá cơ !
![](https://rs.olm.vn/images/medal_mam_non.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_tan_binh.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_chuyen_can.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_cao_thu.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_thong_thai.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_kien_tuong.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
![](https://rs.olm.vn/images/medal_dai_kien_tuong.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_ngoi_sao.png)
![](https://rs.olm.vn/images/medal_win_1.png)
0
2017-07-16 15:20:34
Ta có n + 21 = n + 40
2n+5 chia hết cho 2n-1 <=> 2n-1+6 chia hết 2n-1
Mà 2n-1 chia hết 2n-1
=> Để 2n-1+6 chia hết 2n-1 thì 6 chia hết 2n-1
=> 2n-1 thuôc Ư(6) = {1,2,3,6}
TH1: 2n-1 =1 => n=1
TH2: 2n-1 = 2 => n= 3:2 không là số tự nhiên (loại)
TH3: 2n-1 = 3 => n=2
TH4: 2n-1 = 6 => n= 7:2 không là số tự nhiên (loại)
Vậy n có 2 giá trị là 1 và 2