SOLUTION: 1. Solve the following system of equations using Gaussian elimination method. If there are no solutions, type "N" for both x, y and z. If there are infinitely many solutions, type

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Question 705966: 1. Solve the following system of equations using Gaussian elimination method. If there are no solutions, type "N" for both x, y and z. If there are infinitely many solutions, type "z" for z, and expressions in terms of z for x and y.

0x+7y+0z=-1
5x−5y+6z=-1
−5x+1y+3z=6 ..?
2. Phyllis invested 47000 dollars, a portion earning a simple interest rate of 4 percent per year and the rest earning a rate of 6 percent per year. After one year the total interest earned on these investments was 2620 dollars. How much money did she invest at each rate?
3.A movie theater charges $ 10 for adults and $ 7 for seniors. On a particular day when 347 people paid an admission, the total receipts were $ 2518. Round your answers to the nearest integers.. How many who paid were adults? .. How many who paid were seniors..?
Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!

 0        	7        	0        	1        
 5          -5        	6              -1        
-5        	1        	3        	6        

Swap row 1 and row 2
			
5        	-5        	6        	-1        
0        	7        	0        	1        
-5        	1        	3        	6        

R2/7 to R2
			
5        	-5        	6        	-1        
0        	1        	0        	   1/7  
-5        	1        	3        	6        
	
R1 + R3 to R3
		
5        	-5        	6        	-1        
0        	1        	0        	   1/7  
0        	-4        	9        	5        
		
R1/5 to R1
	
1        	-1        	1   1/5  	-   1/5  
0        	1        	0        	   1/7  
0        	-4        	9        	5        
	
R1 + R2 to R1
		
1        	0        	1   1/5  	-   2/35 
0        	1        	0        	   1/7  
0        	-4        	9        	5        
		
4R2 + R3 to R3
	
1        	0        	1   1/5  	-   2/35 
0        	1        	0        	   1/7  
0        	0        	9        	5   4/7  
		
R3/9 to R3
	
1        	0        	1   1/5  	-   2/35 
0        	1        	0        	   1/7  
0        	0        	1        	  13/21 
	
-6/5*R3 + R1 to R1
		
1        	0        	0        	-   4/5  
0        	1        	0        	   1/7  
0        	0        	1        	  13/21

John

Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
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