Incorrect. Remember that $\displaystyle{{\left({7}{{x}}^{{2}}-{15}\right)}}^{{2}}\usepackage{cmbright}\Huge\$ is equal to $\displaystyle{\left({7}{{x}}^{{2}}-{15}\right)}{\left({7}{{x}}^{{2}}-{15}\right)}\usepackage{cmbright}\Huge\$ . This can be rewritten as $\displaystyle{7}{{x}}^{{2}}{\left({7}{{x}}^{{2}}-{15}\right)}-{15}{\left({7}{{x}}^{{2}}-{15}\right)}\usepackage{cmbright}\Huge\$ . Use this expanded form to simplify the expression.