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Math Help - completing the square

  1. #1
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    completing the square

    Solve 2x sqaured minus negative 4x minus 1 is equal to zero, so 2x^2-4x-1=0, by completing the square. Express in simplest radical form, and could someone show me how to check the answer?
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  2. #2
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    Quote Originally Posted by mcinnes View Post
    Solve 2x sqaured minus negative 4x minus 1 is equal to zero, so 2x^2-4x-1=0, by completing the square. Express in simplest radical form, and could someone show me how to check the answer?
    2x^2 - 4x - 1 = 0

    x^2 - 2x = \frac{1}{2}

    x^2 - 2x + 1 = \frac{1}{2} + 1

    (x - 1)^2 = \frac{3}{2}

    x - 1 = \pm \sqrt{\frac{3}{2}}

    x = 1 \pm \sqrt{\frac{3}{2}}

    EDIT: For a further explanation: http://www.purplemath.com/modules/sqrquad.htm
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