You probably did not create a table of values for this function to see if the resulting ordered pairs matched the graph. Instead, you may have chosen this function because the numbers $\displaystyle-{3}\usepackage{cmbright}\Huge\$ and 1 were in the expression and the graph contains the points $\displaystyle{\left({0},-{3}\right)}\usepackage{cmbright}\Huge\$ and (1, 0). The correct answer is $\displaystyle{f{{\left({x}\right)}}}={3}{x}-{3}\usepackage{cmbright}\Huge\$ .