First use the power property: $\displaystyle{\log}_{{b}}{{M}}^{{n}}={n}\cdot{\log}_{{b}}{M}\usepackage{cmbright}\Huge\$

Then use the product property: $\displaystyle{\log}_{{b}}{M}{N}={\log}_{{b}}{M}+{\log}_{{b}}{N}\usepackage{cmbright}\Huge\$

$\displaystyle{\log}_{{{6}}}{{\left({6}{x}\right)}}^{{2}}={2}\cdot{\log}_{{{6}}}{6}{x}={2}{\left({\log}_{{{6}}}{6}+{\log}_{{{6}}}{x}\right)}={2}{\left({1}+{\log}_{{{6}}}{x}\right)}={2}+{2}\cdot{\log}_{{{6}}}{x}\usepackage{cmbright}\Huge\$