Question 891810
You are starting with {{{log(3,x)+log(5,(4x))=2}}}
Use Change of Base into base 10.


{{{log(10,x)/log(10,3)+log(10,(4x))/log(10,5)=2}}}


{{{log(10,x)*log(10,5)+log(10,(4x))*log(10,3)=2*log(10,3)*log(10,5)}}}


{{{0.69897*log(10,x)+0.477121*log(10,(4x))=2*(0.477121)(0.69897)}}}


{{{log(10,x^0.69897)+log(10,(4x)^0.477121)=0.666987}}}


{{{log(10,(x^0.69897*(4x)^0.477121))=0.666987}}}, 


{{{log(10,(4^0.477121*x^(0.69897+0.477121)))=0.666987}}}


{{{log(10,(4^(0.477121)*x^(1.176091)))=0.666987}}}


{{{log(10,4^0.477121)+log(10,x^1.176091)=0.666987}}}


{{{0.477121*log(10,4)+1.176091*log(10,x)=0.666987}}}


{{{1.176091*log(10,x)=0.666987-0.477121*log(10,4)}}}


{{{highlight_green(log(10,x)=(0.666987-0.477121*log(10,4))/(1.176091))}}}


Can you finish from here?