\(\left(6n+5\right)\text{⋮}\left(3n+1\right)\)
\(\left[\left(6n+2\right)+3\right]\text{⋮}\left(3n+1\right)\)
\(\left[2\left(3n+1\right)+3\right]\text{⋮}\left(3n+1\right)\)
Vì \(2\left(3n+1\right)\text{⋮}\left(3n+1\right)\)
⇒ \(3\text{⋮}\left(3n+1\right)\)
⇒ \(\left(3n+1\right)\) ∈ \(Ư\left(3\right)=\left\{-1;1;-3;3\right\}\)
3n+1 -1 1 -3 3
3n -2 0 -4 2
n \(-\dfrac{2}{3}\) 0 \(-\dfrac{4}{3}\) \(\dfrac{2}{3}\)
Vậy ...