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Math Help - Wheres this minus come from? :(

  1. #1
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    Wheres this minus come from? :(

    Completing this square here guys!

    5x
    + 5x + 11

    Heres how i went through it;

    5[x + x] + 11
    5[(x
    + 1/2) - 1/4] + 11
    5(x + 1/2)
    - 5/4 + 11
    5(x + 1/2)
    + 39/4

    but my book is giving me the answer of

    5(x - 1/2) + 39/4

    and i really can't figure out why. probably something stupidly small, that i've missed, but i can't see it!

    thanks for any help!
    !-- @page { size: 21cm 29.7cm; margin: 2cm } P { margin-bottom: 0.21cm }
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  2. #2
    Super Member craig's Avatar
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    I honestly have no idea, I can only assume that it is a typing error in the book.
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  3. #3
    -1
    e^(i*pi)'s Avatar
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    Your answer looks correct to me too
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  4. #4
    Newbie
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    Oct 2008
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    I've heard its notorious for a fair few errors... guess this is one of them!


    thanks guys!
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