Answer
$2 \ln x+\frac{1}{2} \ln y-\ln z$
Work Step by Step
Use the rule $\ln \left(\frac{A}{B}\right)=\ln A-\ln B$ to obtain:
$$\ln \left(\frac{x^{2} \sqrt{y}}{z}\right)=\ln \left(x^{2} \sqrt{y}\right)-\ln z$$
Use the rule $\ln (AB)=\ln A+\ln B$, and the fact that $\sqrt{x}=x^{\frac{1}{2}}$ to obtain:
\begin{align*}\ln \left(x^{2} \sqrt{y}\right)-\ln z&=\left(\ln x^{2}+\ln \sqrt{y}\right)-\ln z\\
&=\ln x^{2}+\ln y^{1/2}-\ln z\\
\\\text{Use the rule }\ln a^{m}=m\cdot \ln{a} \text{ to obtain:}\\
\\\ln \left(x^{2} \sqrt{y}\right)-\ln z&=2 \ln x+\frac{1}{2} \ln y-\ln z
\end{align*}