Gọi \(d=ƯCLN\left(2n+1;6n+4\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}2n+1⋮d\\6n+4⋮d\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}6n+3⋮d\\6n+4⋮d\end{matrix}\right.\)
\(\Leftrightarrow1⋮d\)
\(\Leftrightarrow d=1\)
\(\LeftrightarrowƯCLN\left(2n+1;6n+4\right)=1\)
\(\Leftrightarrowđpcm\)