Incorrect. Recall that $\displaystyle{16}={{4}}^{{2}}\usepackage{cmbright}\Huge\$ . Also, $\displaystyle{{4}}^{{x}}{{4}}^{{y}}={{4}}^{{{x}+{y}}}\usepackage{cmbright}\Huge\$ , $\displaystyle{{\left({{4}}^{{a}}\right)}}^{{b}}={{4}}^{{{a}{b}}}\usepackage{cmbright}\Huge\$ , and $\displaystyle{{4}}^{{-{{a}}}}=\frac{{1}}{{{4}}^{{a}}}\usepackage{cmbright}\Huge\$ . Use these rules of exponents to simplify this expression.