Answer
$x\approx0.683$
Work Step by Step
First, divide both sides by $3$ to get $$5^x=\frac{9}{3}=3$$ Take the natural log of both sides to get $$\ln 5^x = \ln 3$$ Since $\ln a^b=b \ln a$, the equation becomes $$x \ln 5 = \ln 3$$ Divide both sides by $\ln 5$ to get $$x=\frac{\ln 3}{\ln 5}\approx0.683$$