Question 420710
7r-8s	=-21	.............1	
8r+7s=	89	.............2	
								
multiply (1)by 	7			
Multiply (2) by 	8			
49	r	+	-56	s	=	-147		
64	r	+	56	s	=	712		
								
Add the two equations								
								
113	r	=	565		
								
/	113							
								
r	=	5					
								
plug value of 	r	In (1)				
								
7	r	+	-8	s	=	-21		
35		+	-8	s	=	-21		
			-8	s	=	-21	+	-35
			-8	s	=	-56		
				s	=	7