Question 521930
x1		y1	x2	y2				
-1		3	2	9				
								
slope m =		(y2-y1)/(x2-x1)						
(	9	-	3	)/(	2	-	-1	) 
(	6	/	3	)  				
m=		2      						 

The slope of a line perpendicular to the above line will be the negative reciprocal									
m1*m2=-1									
The slope of the required line will be 			- 1/2						
									
m=	- 1/2	,point	(	4	,	5	)		
Find b by plugging the values of m & the point in									
y=mx+b									
5	=	-2.00	+	b					
b=	7								
m=	- 1/2								
The required equation is		y=-  1/ 2x+7      		
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