Though you correctly substituted the slope 2 into , you then substituted the y-value, 9, from the ordered pair for b. Instead, you should substitute the coordinates of the point (3, 9) for x and y in
and solve for b.
Though you correctly substituted the slope 2 into , you then substituted the y-value, 9, from the ordered pair for b. Instead, you should substitute the coordinates of the point (3, 9) for x and y in
and solve for b.