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| Question 246351:  Please help me solve this linear system with three variables.
 2x-y+2z=-21
 x+5y-z=25
 -3x+2+4z=6
 I had attempted to replicate the example.
 6x-3y+6z=-62
 -6x+4y+8z=12
 y+14z=40
 3x+5y-3z=75
 -3x+2y+4z=6
 17y-z=81
 
 Answer by Alan3354(69443)
      (Show Source): 
You can put this solution on YOUR website! 2x-y+2z=-21 x+5y-z=25
 -3x+2+4z=6
 I had attempted to replicate the example.
 6x-3y+6z=-62 ** = -63, not -62
 -6x+4y+8z=12
 -------------- Add
 y+14z=40 ** -51
 ----------------
 3x+5y-3z=75  ** + 15y, not 5y
 -3x+2y+4z=6
 17y-z=81 --> 17y + z = 81  ** not -z
 ---------------
 Your method is good, but you made some errors.
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 y + 14z = -51  --> y = -14z - 51
 17y + z = 81
 ----------- Since y has a coeff of 1, use substitution.
 17*(-14z-51) + z = 81
 -237z - 867 = 81
 -237z = 948
 z = -4
 --------
 y = 5
 ------
 Sub to find x
 
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