You may have used the incorrect order of operations when computing $\displaystyle-{2}{{\left(-{6}\right)}}^{{0}}\usepackage{cmbright}\Huge\$ . You need to apply the exponent and then multiply, not the other way around. Also, you may have made a mistake with the sign of the second term.

$\displaystyle{{\left(-{6}\right)}}^{{1}}=-{6}\usepackage{cmbright}\Huge\$ , so $\displaystyle-{{\left(-{6}\right)}}^{{1}}={6}\usepackage{cmbright}\Huge\$

The correct answer is 4.