Question 577894
First find the slope of the line through the two points.



m = (y2-y1)/(x2-x1)



m = (15-9)/(7-3)



m = 6/4



m = 3/2



So the slope of the line that passes through the two points is  3/2



The perpendicular slope is simply the negative reciprocal of that slope. Basically, flip the fraction and the sign to get the perpendicular slope.



So the perpendicular slope is -2/3