Correct. Multiply the second equation by 5: $\displaystyle-{10}{a}+{5}{c}={10}\usepackage{cmbright}\Huge\$

Add this to the third equation: $\displaystyle-{10}{a}-{6}{b}={4}\usepackage{cmbright}\Huge\$

Multiply the first equation by 2: $\displaystyle{10}{a}+{8}{b}=-{12}\usepackage{cmbright}\Huge\$

Add these equations: $\displaystyle{2}{b}=-{8}\usepackage{cmbright}\Huge\$ , so $\displaystyle{b}=-{4}\usepackage{cmbright}\Huge\$

Substitute into the third equation: $\displaystyle{24}-{5}{c}=-{6}\usepackage{cmbright}\Huge\$ , so $\displaystyle{c}={6}\usepackage{cmbright}\Huge\$

Substitute the value for c into the second equation: $\displaystyle-{2}{a}+{6}={2}\usepackage{cmbright}\Huge\$ , so $\displaystyle{a}={2}\usepackage{cmbright}\Huge\$