\(2n+1⋮3n-1\)
Mà \(3n-1⋮3n-1\)
\(\Leftrightarrow\left\{{}\begin{matrix}6n+3⋮3n-1\\6n-2⋮3n-1\end{matrix}\right.\)
\(\Leftrightarrow5⋮3n-1\)
\(\Leftrightarrow3n-1\inƯ\left(5\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}3n-1=1\\3n-1=5\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}n=\dfrac{2}{3}\left(loại\right)\\n=2\left(tm\right)\end{matrix}\right.\)
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