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Thread: Finding a number

  1. August 2nd 2006, 05:34 PM #1
    pashah
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    Finding a number

    Find two real numbers that differ by 5 and have a product of 16
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  2. August 2nd 2006, 05:48 PM #2
    ThePerfectHacker
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    Quote Originally Posted by pashah
    Find two real numbers that differ by 5 and have a product of 16
    You need that,
    x-y=5
    xy=16
    Thus,
    x=y+5
    Thus,
    y(y+5)=16
    Thus,
    y^2+5y-16=0
    Thus,
    y=\frac{-5\pm \sqrt{25+64}}{2}
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  3. August 2nd 2006, 05:55 PM #3
    Quick
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    I find it interesting how often the quadratic formula ends up being used
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  4. August 2nd 2006, 05:58 PM #4
    topsquark
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    Quote Originally Posted by Quick
    I find it interesting how often the quadratic formula ends up being used
    Trust me, if cubics were easier to solve we'd be seeing a lot more of those!

    -Dan
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