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Math Help - Solving system of equations with 3 variables.

  1. #1
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    Unhappy Solving system of equations with 3 variables.

    The question is:

    16x+12y+4z=364
    4x+37+4z=100

    What is the value of 20x+15y?

    In school, whenever I did problems with 3 variables, there were always 3 equations given. is this possible to solve?
    Last edited by mr fantastic; August 7th 2011 at 11:25 PM.
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  2. #2
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    Re: Solving system of equations with 3 variables help!

    Is the second equation as written, or should the middle term be 37y?
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  3. #3
    Super Member Bacterius's Avatar
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    Re: Solving system of equations with 3 variables help!

    Note how the 4z term appears in both equations... do you think you may be able to remove it?
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    Re: Solving system of equations with 3 variables help!

    Quote Originally Posted by Prove It View Post
    Is the second equation as written, or should the middle term be 37y?

    OH, RIGHT, it is 37y! sorry!

    and yes, I've tried to remove the 4z by combination, but I don't know what to do from there!
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  5. #5
    MHF Contributor Siron's Avatar
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    Re: Solving system of equations with 3 variables help!

    Try to make other combinations until you've an equation in one variable.
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  6. #6
    Member anonimnystefy's Avatar
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    Re: Solving system of equations with 3 variables help!

    hi guys i got 455.
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  7. #7
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    Re: Solving system of equations with 3 variables.

    Quote Originally Posted by cindyli319 View Post
    The question is:

    16x+12y+4z=364
    4x+37+4z=100

    What is the value of 20x+15y?

    In school, whenever I did problems with 3 variables, there were always 3 equations given. is this possible to solve?
    It seems more likely that the 37 should be 3y.

    You then have:
    16x+12y+4z=364
    -4x -3y -4z=-100

    Add the equations to get 12x+9y. Then multiply be 5/3 .
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