0;if x=1==>\log_31-\log_{15}1\neq\log_{15}125==>0\neq\log_{15}125;\\
\frac{\ln x}{\ln 3}- \frac{\ln x}{\ln 15}= \frac{\ln125}{\ln15} ;\\
\ln x( \frac{1}{\ln 3}-\frac{1}{\ln15} )= \frac{\ln 125}{\ln 15};\\
\ln x( \frac{\ln15-\ln3}{\ln15\ln3} )= \frac{\ln125}{\ln15};\\
\ln x( \frac{\ln5+\ln3-\ln3}{\ln3} )=\ln125;\\
\ln x= \frac{\ln125\ln3}{\ln5}= \frac{\ln5^3\ln3}{\ln5}= \frac{3\ln5\ln3}{\ln5}=3\ln3=\ln3^3=\ln27;\\
e^{\ln x}=e^{\ln27};\\
x=27; " alt="\log_3x-\log_{15}x=\log_{15}125;\\
x>0;if x=1==>\log_31-\log_{15}1\neq\log_{15}125==>0\neq\log_{15}125;\\
\frac{\ln x}{\ln 3}- \frac{\ln x}{\ln 15}= \frac{\ln125}{\ln15} ;\\
\ln x( \frac{1}{\ln 3}-\frac{1}{\ln15} )= \frac{\ln 125}{\ln 15};\\
\ln x( \frac{\ln15-\ln3}{\ln15\ln3} )= \frac{\ln125}{\ln15};\\
\ln x( \frac{\ln5+\ln3-\ln3}{\ln3} )=\ln125;\\
\ln x= \frac{\ln125\ln3}{\ln5}= \frac{\ln5^3\ln3}{\ln5}= \frac{3\ln5\ln3}{\ln5}=3\ln3=\ln3^3=\ln27;\\
e^{\ln x}=e^{\ln27};\\
x=27; " align="absmiddle" class="latex-formula">