Make a table of values with inputs $\displaystyle-{1}\usepackage{cmbright}\Huge\$ , $\displaystyle{0}\usepackage{cmbright}\Huge\$ , and $\displaystyle{2}\usepackage{cmbright}\Huge\$ , for example. Evaluate the function for each value of x, and record the output, $\displaystyle{f{{\left({x}\right)}}}\usepackage{cmbright}\Huge\$ . Each row in your table forms an ordered pair. These points would be $\displaystyle{\left(-{1},-{5}\right)}\usepackage{cmbright}\Huge\$ , $\displaystyle{\left({0},-{2}\right)}\usepackage{cmbright}\Huge\$ , and $\displaystyle{\left({2},{4}\right)}\usepackage{cmbright}\Huge\$ . The graph contains these points and is a straight line.