Use the product property on the left side: $\displaystyle{\log{{4}}}{x}+{\log{{2}}}={\log{{\left({4}{x}\cdot{2}\right)}}}={\log{{8}}}{x}\usepackage{cmbright}\Huge\$

The equation becomes $\displaystyle{\log{{8}}}{x}={\log{{48}}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{8}{x}={48}\usepackage{cmbright}\Huge\$ .

Divide both sides by 8: $\displaystyle{x}={6}\usepackage{cmbright}\Huge\$