Gọi d là ƯCLN (2n+1, 4n+3)
\(\Rightarrow\hept{\begin{cases}2n+1⋮d\\4n+3⋮d\end{cases}}\Leftrightarrow\hept{\begin{cases}4n+2⋮d\\4n+3⋮d\end{cases}}\Rightarrow1⋮d\Rightarrow d=1\\ \)
Gọi \(ƯCLN\left(2n+1;4n+3\right)\) là \(d\left(d\ne0\right)\)
Theo bài ra ta có :
\(\hept{\begin{cases}2n+1⋮d\\4n+3⋮d\end{cases}\Rightarrow\hept{\begin{cases}2\left(2n+1\right)⋮d\\4n+3⋮d\end{cases}\Rightarrow}\hept{\begin{cases}4n+2⋮d\\4n+3⋮d\end{cases}}}\)
\(\Rightarrow\left(4n+3\right)-\left(4n+2\right)⋮d\)
\(\Rightarrow1⋮d\)
\(\Rightarrow d\in\left\{1;-1\right\}\)
Vì \(d\)là \(ƯCLN\Rightarrow d=1\)
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