Multiply the first equation by $\displaystyle-{2}\usepackage{cmbright}\Huge\$ : $\displaystyle-{2}{x}+{4}{y}={10}\usepackage{cmbright}\Huge\$

Add this to $\displaystyle{2}{x}+{3}{y}={11}\usepackage{cmbright}\Huge\$ to get: $\displaystyle{7}{y}={21}\usepackage{cmbright}\Huge\$

Solve for y to get $\displaystyle{y}={3}\usepackage{cmbright}\Huge\$ , and substitute this into the first equation:

$\displaystyle{x}-{2}{\left({3}\right)}=-{5}\usepackage{cmbright}\Huge\$ or $\displaystyle{x}-{6}=-{5}\usepackage{cmbright}\Huge\$ , so $\displaystyle{x}={1}\usepackage{cmbright}\Huge\$