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Math Help - Solving this Quadratic Equation!

  1. #1
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    Solving this Quadratic Equation!

    x^2 ² + 2x - 5 = 0<br />
    Can you answer this please?? Showing all working out! Thanks!

    I'm in my GCSE year at school.

    the first x is squared, the 2 wont show up for some reason
    Last edited by Jameson; November 8th 2007 at 04:01 AM. Reason: fixed notation
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  2. #2
    Senior Member DivideBy0's Avatar
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    Melbourne, Australia
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    Completing the square:

    x^2+2x-5=0

    x^2+2x = 5

    x^2+2x+1=5+1

    (x+1)^2=6

    x+1=\pm \sqrt{6}

    x=-1\pm \sqrt{6}

    GFSQ (General Formula for Solution of Quadratics) i.e. Quadratic Formula:

    x = \frac{-(2) \pm \sqrt{(2)^2 - 4(1)(-5)}}{2(1)}

    x=\frac{-2 \pm \sqrt{24}}{2}

    x=\frac{-2\pm 2\sqrt{6}}{2}

    x=-1 \pm \sqrt{6}
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  3. #3
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    Wow that answer was great! I'm not very good at maths though and that Quadratic formula as just babble to me haha, sorry about that.

    Could you explain where the one came from?
    I learn easier with an explanation, formula is a new language for me haha!

    Thank you!
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