\(\left(\dfrac{3}{5}\right)^{2n-1}=\left(\dfrac{9}{25}\right)^3\)
\(\left(\dfrac{3}{5}\right)^{2n-1}=\left[\left(\dfrac{3}{5}\right)^2\right]^3\)
\(\left(\dfrac{3}{5}\right)^{2n-1}=\left(\dfrac{3}{5}\right)^6\)
\(2n-1=6\)
\(2n=7\)
\(n=\dfrac{7}{2}\notin N\)
Vậy ko có số tự nhiên n thỏa mãn