Question 430100

gas cost x
electricity cost y

100x+500y=352	.............1			
150x+400y=304	.............2			
Eliminate y										
multiply (1)by 	-4								
Multiply (2) by	5								
-400x-2000y=-1408				
750x+2000y=1520				
Add the two equations										
350x=	112				
/350									
x=0.32	gas unit cost				
plug value of 			x	in (1)						
100x+500y=352				
32+500y=352				
500y=352-32		
500y=320				
y=0.64	electricity cost	
CHECK										
										
100	x	+	500	y	=	352				
32			320		=	352				
			352		=	352