Answer
$\ln{\left(\frac{9}{5}\right)}$ or $\ln{1.8}$
Work Step by Step
RECALL:
$\ln{a}-\ln{b}=\ln{\left(\frac{a}{b}\right)}$
Use the rule above to obtain:
\begin{align*}
\ln{18}-\ln{10}&=\ln{\left(\frac{18}{10}\right)}\\
&=\ln{\left(\frac{9}{5}\right)}\\
&=\ln{1.8}
\end{align*}
