Simplify the numerator: $\displaystyle-{\left|{8}-{14}\right|}=-{\left|-{6}\right|}=-{6}\usepackage{cmbright}\Huge\$

Simplify the denominator: $\displaystyle{12}-{3}{\left|{5}+{\left(-{3}\right)}\right|}={12}-{3}{\left|{2}\right|}={12}-{3}\cdot{2}={12}-{6}={6}\usepackage{cmbright}\Huge\$

Divide: $\displaystyle\frac{{-{6}}}{{6}}=-{1}\usepackage{cmbright}\Huge\$