a) Chịu
b) Gọi \(d=ƯCLN\left(3n+1;5n+2\right)\) \(\left(d\in N\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}3n+1⋮d\\5n+2⋮d\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}15n+5⋮d\\15n+6⋮d\end{matrix}\right.\)
\(\Leftrightarrow1⋮d\)
Vì \(d\in N;1⋮d\Leftrightarrow d=1\)
\(\LeftrightarrowƯCLN\left(3n+1;5n+2\right)=1\)
Vậy phân số \(\dfrac{3n+1}{5n+2}\) tối giản với mọi n