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

The equation becomes $\displaystyle{\log{{4}}}{x}={\log{{16}}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{4}{x}={16}.\usepackage{cmbright}\Huge\$

Divide both sides by 4: $\displaystyle{x}={4}\usepackage{cmbright}\Huge\$