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Math Help - Help Solving a Quadratic

  1. #1
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    Help Solving a Quadratic

    I am having trouble figuring out this problem. I know that there may not be a real solution, but we have to show the steps to solving this theoretical quadratic. If someone could show me the steps that would be awesome!

    3x^2 + xy + 2y^2 = 0
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  2. #2
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by KarlosK View Post
    I am having trouble figuring out this problem. I know that there may not be a real solution, but we have to show the steps to solving this theoretical quadratic. If someone could show me the steps that would be awesome!

    3x^2 + xy + 2y^2 = 0
    Is it a quadratic in x or y?
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  3. #3
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    I don't really understand your question if it is in x or y? She just asked for us to solve this using the quadratic equation. I assume that there is going to be no number answer
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  4. #4
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    Quote Originally Posted by KarlosK View Post
    I don't really understand your question if it is in x or y? She just asked for us to solve this using the quadratic equation. I assume that there is going to be no number answer
    If it's a quadratic in y you need to solve for y=f(x)
    If it's a quadratic in x you need to solve for x = f(y)
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  5. #5
    Senior Member Stroodle's Avatar
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    Quote Originally Posted by KarlosK View Post
    I don't really understand your question if it is in x or y? She just asked for us to solve this using the quadratic equation. I assume that there is going to be no number answer
    If you're solving for x and using the quadratic formula: x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} let a=3,\ b=y and c=2y^2

    Spoiler:
    x=\frac{-y\pm\sqrt{-23y^2}}{6}
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  6. #6
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    What you did there makes sense. I understand how to get to that point now. So basically she is just looking for how I would come to the solution... but there will not be an actual number solution?
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  7. #7
    Senior Member Stroodle's Avatar
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    There are no real solutions, if that is what you are referring to, as y^2 will be positive, and you cant take the square root of a negative value.
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  8. #8
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    Talking

    What expression do you get inside the square root?

    Is there any value of y for which this expression will not be negative?
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