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Math Help - Subtracting polynomials

  1. #1
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    Subtracting polynomials

    Just want to check what to do next, and any errors I made

    Question: Add or subtract the following:

    Having trouble typing equations in again so heres a quick pic
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    Then it says to list any restrictive values.

    Are restrictive and undefined values different things?
    Last edited by Urpes; July 9th 2013 at 09:40 AM.
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  2. #2
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    Re: Subtracting polynomials

    Hello, Urpes!

    You made some errors . . .


    \displaystyle \text{Simplify: }\;\frac{x+2}{(x-5)(x+2)} - \frac{2(x-7)}{(x-7)(x-5)}

    Note that:- x \,\ne\, \text{-}2, 5, 7

    We have: . \dfrac{x+2}{(x-5)(x+2)} - \dfrac{2(x-7)}{(x-7)(x-5)}

    Reduce: . \dfrac{1}{x-5} - \frac{2}{x-5}

    Combine: . \dfrac{1-2}{x-5} \;\;=\;\;\frac{-1}{x-5}

    Therefore: . \dfrac{1}{5-x}
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  3. #3
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    Re: Subtracting polynomials

    Ah I see, the only thing I don't get is the very last part? How did you get the denominator to be 5-x
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  4. #4
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    Re: Subtracting polynomials

    Soroban multiplied the top and bottom by -1 to get the last line
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