Correct. $\displaystyle{x}-{4}={0}\usepackage{cmbright}\Huge\$ or $\displaystyle{x}-{6}={0}\usepackage{cmbright}\Huge\$ , so $\displaystyle{x}={4}\usepackage{cmbright}\Huge\$ or $\displaystyle{x}={6}\usepackage{cmbright}\Huge\$ . The other solution is 6.