Incorrect. Remember to distribute the negative sign to all the terms in the second parentheses. Then, try putting like terms close together so that your expression resembles the following: $\displaystyle{102}{{x}}^{{2}}{y}-{21}{{x}}^{{2}}{y}-{5}{{x}}^{{2}}+{8}{{x}}^{{2}}+{3}{y}+{16}\usepackage{cmbright}\Huge\$ . Now you can add and subtract like terms.