Question 178208This question is from textbook saxon algebra 2
: Help!
Solve the system of equations.
x+y+z=4
2x+3y-z=18
3x-y+2z=-2
The -z confuses me.
This question is from textbook saxon algebra 2
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Solve the system of equations.
x+y+z=4
2x+3y-z=18
3x-y+2z=-2
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Eliminate z.
Add the 1st and 2nd eqns.
x + y + z = 4
2x+3y - z = 18
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3x+4y = 22
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Multiply the 2nd eqn by 2, then add it to the 3rd
4x + 6y - 2z = 36
3x - 1y + 2z = -2
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7x + 5y = 34
Now there are 2 eqns in x and y.
3x + 4y = 22
7x + 5y = 34
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Multiply the 1st by 5, and the 2nd by 4
15x + 20y = 110
28x + 20y = 136
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Subtract
-13x = -26
x = 2
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Sub x into 3x + 4y = 22
3*2 + 4y = 22
4y = 16
y = 4
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Sub x and y into x+y+z=4
2 + 4 + z = 4
z = -2
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