So point-slope form is (y-y1) = m(x-x1). So first find m. m = (y2-y1) / (x2-x1) So for your problem m = (-4-2) / (1--8) = -6/9 = -2/3. Then plug the slope and a point into the point-slope equation so you can either get: y-2 = (-2/3)*(x+8) or y+4 = (-2/3)*(x-1). Both are valid.