Incorrect. You simplified the expression $\displaystyle{\left(-\frac{{1}}{{2}}{{x}}^{{2}}{{y}}^{{4}}\right)}{\left(\frac{{1}}{{2}}{{x}}^{{2}}{{y}}^{{2}}\right)}\usepackage{cmbright}\Huge\$ , not $\displaystyle{{\left(-\frac{{1}}{{2}}{{x}}^{{2}}{{y}}^{{4}}\right)}}^{{2}}\usepackage{cmbright}\Huge\$ . Remember that you must multiply the coefficient by itself and multiply the exponents within the parentheses by the exponent on the outside of the parentheses.