You may have substituted 3 for x instead of $\displaystyle-{3}\usepackage{cmbright}\Huge\$ . You need to find the value of $\displaystyle-{{\left(-{3}\right)}}^{{3}}+{5}{{\left(-{3}\right)}}^{{2}}-{7}\usepackage{cmbright}\Huge\$ . The correct answer is 65.