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Math Help - [SOLVED] Completing the square

  1. #1
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    [SOLVED] Completing the square

    How do you complete the square of this problem?

    5-4x-x^2
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  2. #2
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    Quote Originally Posted by Mike9182 View Post
    How do you complete the square of this problem?

    5-4x-x^2
    Divide the expression by -1 to get a positive coefficient of x^2

    -(x^2+4x-5)

    When completing the square divide b by 2:

    (x+2)^2. However this gives us x^2+4x+4 so we must take 4 to get the expression to work (and don't forget c)

    -[(x+2)^2 - 4 -5] = -[(x+2)^2-9] = 9-(x+2)^2
    Last edited by e^(i*pi); January 26th 2010 at 09:58 AM. Reason: oops minus sign
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  3. #3
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    Thanks, what about this one? 4x-x^2?

    EDIT: I found the answer.
    Last edited by Mike9182; January 26th 2010 at 11:18 AM. Reason: found the answer
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