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Question 824681:  Solve systems of three variables.  linear eqations  
2x+2y+z=1 
-x+y+2z=3 
x+2y+4z=0 
 Answer by TimothyLamb(4379)      (Show Source): 
You can  put this solution on YOUR website! --- 
2x+2y+z=1 
-x+y+2z=3 
x+2y+4z=0 
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copy and paste the above standard form linear equations in to this (matrix method) solver: 
https://sooeet.com/math/system-of-linear-equations-solver.php 
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answer: 
x= -2 
y= 3 
z= -1 
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NOTE TO STUDENT: 
now solve by elimination: 
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-x+y+2z=3 
x+2y+4z=0 
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add this sub-system and call it A: 
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3y+6z=3 
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2x+2y+z=1 
2(-x+y+2z=3) 
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add this sub-system and call it B: 
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4y+5z=7 
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the A and B sub-system: 
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3y+6z=3 
4y+5z=7 
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add the A and B sub-system: 
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-4(3y+6z=3) 
3(4y+5z=7) 
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-9z=9 
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z = -1 
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substitute z in B: 
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4y+5(-1)=7 
4y=12 
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y = 3 
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substitute y and z in any of the original equations: 
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x+2(3)+4(-1)=0 
x+6-4=0 
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x = -2 
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answer by elimination: 
x= -2 
y= 3 
z= -1 
NOTE: the matrix method (used by the above solver), and the elimination method agree 
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Solve and graph linear equations: 
https://sooeet.com/math/linear-equation-solver.php 
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Solve quadratic equations, quadratic formula: 
https://sooeet.com/math/quadratic-formula-solver.php 
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Solve systems of linear equations up to 6-equations 6-variables: 
https://sooeet.com/math/system-of-linear-equations-solver.php 
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