Answer
$x=3e^4$
Work Step by Step
Recall:
$\ln{a}-\ln{b} = \ln{\left(\frac{a}{b}\right)}$
Thus, using the rule above gives:
\begin{align*}
\ln{\left(\frac{x}{3}\right)}&=4
\end{align*}
Recall:
$\ln{x}=a \longleftrightarrow e^a=x$
Hence,
\begin{align*}
\ln{\left(\frac{x}{3}\right)}=4 &\longrightarrow \frac{x}{3}=e^4\\\\
&x=3 \cdot e^4
\end{align*}
Check:
\begin{align*}
\ln{(3\cdot e^4)}- \ln{3}&=4\\\\
\ln{\left(\frac{3e^4}{3}\right)}&=4\\\\
\ln{e^4}&=4\\\\
4&=4
\end{align*}
