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Math Help - roots question

  1. #1
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    roots question

    i tried to work out this question but i cant make it
    find the value of k for which the equation xsquared-2x/4x+7 = k-1/k+1 has roots equal in magnitude but opposite in sign
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  2. #2
    Lord of certain Rings
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    Quote Originally Posted by clutch View Post
    i tried to work out this question but i cant make it
    find the value of k for which the equation xsquared-2x/4x+7 = k-1/k+1 has roots equal in magnitude but opposite in sign
    Dear clutch,

    Please use parentheses while typing your question, so that you make it clear and the helpers here, dont waste time over a wrongly assumed question.

    Should your equation read \frac{x^2 - 2x}{4x + 7} = \frac{k-1}{k+1}?
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  3. #3
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    yes like that tks!
    \frac{x^2 - 2x}{4x + 7} = \frac{k-1}{k+1}<br />
    Last edited by mr fantastic; January 2nd 2009 at 07:15 PM. Reason: Fixed the copied latex - the bug strikes again
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  4. #4
    Lord of certain Rings
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    Ok then...I will give you couple of hints:

    1) Do you understand that if you cross multiply and group terms carefully, you will get a quadratic?

    2) Do you realize that if a quadratic has "roots equal in magnitude but opposite in sign", then the sum of roots is 0 and thus the coefficient of the linear term in the quadratic is 0?
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