Question 999307
2x + 4y − 2z = 14 
 x + 3y + 4z = 10 
 x + 2y − z = 18
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 x + 3y + 4z = 10 
 x + 2y − z = 18
------------------------- Subtract
y + 5z = -8  Eqn A
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2x + 4y − 2z = 14 
2x + 6y + 8z = 20 -- 2nd eqn times 2
--------------------------- Subtract
-2y - 10z = -6
-2y - 10z = 16  Eqn A times -2
----------------------- Subtract
0 = -22 --> inconsistent, no solution
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These are all the same problem, just different numbers.
Do them like that.