The straight line is given by the equation y=kx+b We substitute coordinates of points -21=-66k+b (1) 2=-67k+b (2) We give a system of equations Solution of this system: (1) b=66k-21 (2) 20=-67k+66k-21 20=-k-21 k=-21-20 k=-41 b=-41*66-21=-2727 y=-41x-2727
