You correctly substituted the slope (m) into $\displaystyle{y}={m}{x}+{b}\usepackage{cmbright}\Huge\$ , but you then substituted the y-value from the ordered pair ( $\displaystyle-{3}\usepackage{cmbright}\Huge\$ ) for b. Instead, you should substitute the coordinates of the point $\displaystyle{\left({4},-{3}\right)}\usepackage{cmbright}\Huge\$ for x and y in $\displaystyle{y}=-\frac{{1}}{{4}}{x}+{b}\usepackage{cmbright}\Huge\$ , and solve for b.