If you multiply the third equation by 2 and add it to the first equation, the resulting statement is $\displaystyle{0}={0}\usepackage{cmbright}\Huge\$ . If you multiply the third equation by 3 and add it to the second equation, the resulting statement is also $\displaystyle{0}={0}\usepackage{cmbright}\Huge\$ . This means that the system has an infinite number of solutions.