ta co:\(5+n⋮n+1\)
\(\Rightarrow4+\left(1+n\right)⋮n+1\)
\(\Rightarrow4⋮n+1\)
\(\Rightarrow n+1\in U\left(4\right)=\left\{1;2;4;-1;-2;-4\right\}\)
Ta co bang sau:
n+1 | 1 | 2 | 4 | -1 | -2 | -4 |
n | 0 | 1 | 3 | -2 | -3 | -5 |
(5+n)\(⋮\)(n+1)
=> (5+n) - (n+1)\(⋮\)n+1
=>4 \(⋮\)n+1
=> n = 1;-1;2;-2;4;-4
=> n = 0;-2;-1;-3;3;-5
ta có : 5+n chia hết n+1
suy ra : 4+(1+n) chia hết n+1
suy ra : 4 chia hết n+1
suy ra: n thuộc ước (4) = 1;2;4;-1;-2;-4