SOLUTION: 3x-4y-z=25 2x+y+4z=29 X=-2y X=? Y=? Z=?

Algebra ->  Expressions-with-variables -> SOLUTION: 3x-4y-z=25 2x+y+4z=29 X=-2y X=? Y=? Z=?       Log On


   

Question 990233: 3x-4y-z=25
2x+y+4z=29
X=-2y
X=? Y=? Z=?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
3x-4y-z=25
2x+y+4z=29
X=-2y
---------------
Sub for x in eqn 1 and eqn 2:
3x-4y-z=25
2x+y+4z=29
---
3(-2y) - 4y - z = 25
-10y - z = 25 Eqn A
--
2(-2y) + y + 4z = 29
-3y + 4z = 29
-10y - z = 25 Eqn A
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-3y + 4z = 29
-40y -4z = 100 Eqn A times 4
-------------------------------------- Add
-43y = 129
y = -3 *******************************
Sub for y and find x & z