Incorrect. Substitute the values for x into the equation to get $\displaystyle{{8}}^{{0}}\usepackage{cmbright}\Huge\$ , $\displaystyle{{8}}^{{1}}\usepackage{cmbright}\Huge\$ , $\displaystyle{{8}}^{{2}}\usepackage{cmbright}\Huge\$ , and $\displaystyle{{8}}^{{3}}\usepackage{cmbright}\Huge\$ . Simplify each of these.