Question 810648
x1		y1	x2	y2				
2      		1      	-7      	2    				
								
slope m =		(y2-y1)/(x2-x1)						
(	2    	-	1    	)/(	-7    	-	2    	)
(	1    	/	-9    	)  				
m=		-  1/ 9