While calculating $\displaystyle{2}{{\left(-{2}\right)}}^{{3}}-{3}{{\left(-{2}\right)}}^{{2}}+{4}\usepackage{cmbright}\Huge\$ , you may have thought that $\displaystyle-{3}{{\left(-{2}\right)}}^{{2}}\usepackage{cmbright}\Huge\$ was positive. Remember to evaluate exponents before multiplication.