<PRE><B>Question 566004</B>
the point of intersection of 3x-5y-10=0 and x+y+1=0.

the point of intersection can be found by solving the linear system

3	x		-5	y	=	10	.............1	
1	x	+	1	y	=	-1	.............2	
Eliminate y								
multiply (1)by 		1						
Multiply (2) by		5						
3	x		-5	y	=	10		
5	x		5	y	=	-5		
Add the two equations								
8	x				=	5		
/	8							
x	=	5/8						
plug value of 			x	in (1)				
3	x		-5	y	=	10		
15/8			-5	y	=	10		
			-5	y	=	65/8					-5	y	=	65/8		
				y	=	65/40=13/8

The coordinates of intersection are (5/8 , 13/8)

The other point is (2,1)	

x1		y1	x2	y2			
  5/ 8		13/8	2    	1    			
							
slope m =		(y2-y1)/(x2-x1)					
(	1    	-	13/8	)/(	2    	-	 5/8
(	-5/8	/	11/8	)  			
m=		-  5/11					
							
Plug value of  the slope  and point (	 5/8	,	13/8	) in
Y 	=	m	x 	+	b		
13/8	=	- 2/7	+	b			
b=	13/8	+ 2/7				
b=	21/11						
So the equation  will be							
Y 	=	- 4/9	x 	+	17/9		
m.ananth@hotmail.ca							
	


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