Question 1128334: solve by elimination
x-y-2x=4
-x+2y+z=1
-x+y-3z=11
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! solve by elimination
x-y-2z =4 --- Eqn 1
-x+2y+z=1 --- Eqn 2
-x+y-3z=11 -- Eqn 3
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Eliminate 1 of the 3 variables.
Start with x, since all 3 coefficients are 1 or -1
---
x-y-2z =4 --- Eqn 1
-x+2y+z=1 --- Eqn 2
------------------------------ Add
y + z = 5 --- Eqn A
---
x-y-2z =4 --- Eqn 1
-x+y-3z=11 -- Eqn 3
---------------------------- Add
-5z = 15
z = -3
*******************
y + z = 5 --- Eqn A
y - 3 = 5
y = 8
*******************
x-y-2z =4 --- Eqn 1
x - 8 + 6 = 4
x = 6
(6,8,-3)
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