Question 452242
3x+9y=21	.............1	
-8x+y=19	.............2	
Eliminate y								
multiply (1)by 		1						
Multiply (2) by		-9						
3x+9y=21		
72x-9y=-171		
Add the two equations								
75x=	-150		
/75							
x=-2						
plug value of 	x	in (1)				
3x+9y=21		
-6+9y=21		
9y=21+6
9y=27		
y=3		
................... 


7m+n=1	.............1	
m-2n=13	.............2	
Eliminate y								
multiply (1)by 		2						
Multiply (2) by		1						
14m+2n=	2		
m-2n=	13		
Add the two equations								
15m=	15		
/15							
m=	1						
plug value of 			m	in (1)				
7m+n=1		
7+1n=1		
n=1-7
n=-6