Question 419050
1.  x-6y=23
    2x-6y=28
..................

x-6y=23	.............1	
2x-6y=28.............2	
								
multiply (1)by 	1			
Multiply (2) by -1			
x-6y=23		
-2x+6y=	-28		
								
Add the two equations								
								
-x=-5		
								
/-1							
								
x=5						
								
plug value of x in (1)								
								
x-6y=23		
5-6y=23		
-6y=23-5
-6y=18		
y=-3		

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2.  Ellen wishes to mix candy worth $3.44 per pound with candy worth $9.96 per pound to form 24 pounds of a mixture worth $8.33 per pound. How many pounds of the more expensive candy should she use?

3.44	----------------	x
9.96	----------------	24-x
8.33	----------------	24
....................

3.44x+9.96(24-x)=8.33*24
3.44x+239.04-9.96x=199.92		
3.44x-9.96x=199.92-239.04		
-6.52x	=-39.12							
/-6.52										
x=6 pounds of $3.44 candy		
18 pounds of $9.96 candy