You may have made a mistake with a sign. Remember that a negative times a positive is negative.

$\displaystyle{2}{\left({3}\right)}+{3}{\left(-{1}\right)}={3}\usepackage{cmbright}\Huge\$ or $\displaystyle{6}-{3}={3}\usepackage{cmbright}\Huge\$ or $\displaystyle{3}={3}\usepackage{cmbright}\Huge\$

The statement is true, so the ordered pair $\displaystyle{\left({3},-{1}\right)}\usepackage{cmbright}\Huge\$ is a solution to the equation.

The correct answer is $\displaystyle{4}{x}={8}{y}+{4}\usepackage{cmbright}\Huge\$ .