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September 20th, 2011, 05:56 AM   #1
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Linear equation in three variables

What is the value of y in the following system of equations?
x + y + z = 75 ; -2x + y z = -15
a. 0
b. 5
c. 15
d. 60
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September 20th, 2011, 08:10 AM   #2
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Is something mistyped or omitted? The equations imply that y = 30 + x/2 = 45 - z/3.
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September 20th, 2011, 12:42 PM   #3
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Re: Linear equation in three variables

Quote:
Originally Posted by Qwertyqwerty
What is the value of y in the following system of equations?
x + y + z = 75 ; -2x + y z = -15
a. 0
b. 5
c. 15
d. 60
You have 3 unknowns - you need 3 equations.
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September 20th, 2011, 03:31 PM   #4
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With only the two equations, y can't be calculated, but you can calculate 3x + 2z.
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September 20th, 2011, 10:38 PM   #5
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Re: Linear equation in three variables

This is it, word for word.

Thanks anyway.
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