$$(\frac{5}{3})^{-5}\times(\frac{5}{3})^{-3}=(\frac{5}{3})^{-2x}$$
$x=4$
$x=\frac{\pi n_{1}i}{\ln(\frac{3}{5})}-\log_{\frac{3}{5}}\left(\frac{625}{81}\right)$
$n_{1}\in \mathrm{Z}$