Incorrect. Notice that $\displaystyle{{\left({6}{{x}}^{{3}}-{12}{{x}}^{{2}}\right)}}^{{2}}\usepackage{cmbright}\Huge\$ is the square of a difference. Use the formula $\displaystyle{{\left({a}-{b}\right)}}^{{2}}={{a}}^{{2}}-{2}{a}{b}+{{b}}^{{2}}\usepackage{cmbright}\Huge\$ to help you simplify this expression.