Question 1025468:  Which answer correctly shows the first step that can be used to correctly solve the system of equations?
 
5x + 2y = 4  
3x + 4y + 2z = 6  
7x + 3y + 4z = 29
 
 
A.	 
3x + 4y + 2z = 6  →     3x + 4y + 4z = 6  
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
 
-4x -  y  =- 23
 
B.	 
3x + 4y + 2z = 6 →     6x + 8y + 4z = 12  
 7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
 
-x + 5y  = -17
 
C.	 
3x + 4y + 2z = 6 →     6x + 8y + 4z =  6 
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 2
 
-x + 5y =- 23
 
D.	 
3x + 4y + 2z = 6 →     6x + 8y + 4z = 12  
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
 
-x + 8y = 41
 
Thanks in advance, this has been a difficult problem for me.
 
 
 Answer by Edwin McCravy(20064)      (Show Source): 
You can  put this solution on YOUR website! 
5x + 2y = 4 
3x + 4y + 2z = 6 
7x + 3y + 4z = 29
A.	
3x + 4y + 2z = 6  →     3x + 4y + 4z = 6 
Oh,oh! They forgot to multiply the 6 by 2>
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
-4x -  y  =- 23
B.	
3x + 4y + 2z = 6 →     6x + 8y + 4z = 12 
 7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
-x + 5y  = -17
C.	
3x + 4y + 2z = 6 →     6x + 8y + 4z =  6
Oh,oh! They forgot to multiply the 6 by 2>
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 2
-x + 5y =- 23
D.	
3x + 4y + 2z = 6 →     6x + 8y + 4z = 12 
7x + 3y + 4z = 29 → (-)7x + 3y + 4z = 29
-x + 8y = 41
Oh,oh! They didn't subtract 3y from 8y,
and also they added 29 to 12 when they should 
have subtracted.>
Edwin  
 
  | 
 
  
 
 |   
 
 |