Question 536687
x1		y1	x2	y2				
3	*	9	7	15				
								
slope m =		(y2-y1)/(x2-x1)						
(	15	-	9	)/(	7	-	3	) 
(	6	/	4	)  				
m=		3/ 2

The slope of perpendicular line = -2/3 because m1*m2 = -1