Multiply the polynomial by $\displaystyle-{1}\usepackage{cmbright}\Huge\$ : $\displaystyle{\left(-{1}\right)}{\left({8}{{c}}^{{3}}+{10}{{c}}^{{2}}-{6}{c}-{5}\right)}\usepackage{cmbright}\Huge\$

Distribute $\displaystyle-{1}\usepackage{cmbright}\Huge\$ to each term in the polynomial: $\displaystyle{\left(-{1}\right)}{\left({8}{{c}}^{{3}}\right)}+{\left(-{1}\right)}{\left({10}{{c}}^{{2}}\right)}+{\left(-{1}\right)}{\left(-{6}{c}\right)}+{\left(-{1}\right)}{\left(-{5}\right)}\usepackage{cmbright}\Huge\$

Multiply each coefficient by $\displaystyle-{1}\usepackage{cmbright}\Huge\$ : $\displaystyle-{8}{{c}}^{{3}}+{\left(-{10}{{c}}^{{2}}\right)}+{6}{c}+{5}\usepackage{cmbright}\Huge\$

Rewrite addition of a negative term as subtraction: $\displaystyle-{8}{{c}}^{{3}}-{10}{{c}}^{{2}}+{6}{c}+{5}\usepackage{cmbright}\Huge\$