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Math Help - Quadratic Formula

  1. #1
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    Exclamation Quadratic Formula

    Are the solutions to x^2 - 4x - 8 really (4 +/- sqrt(48))/2?

    Because everytime I try working it out using the quadratic formula, my answer comes out with a 16 instead of the 4? ??
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  2. #2
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    Quote Originally Posted by xwrathbringerx View Post
    Are the solutions to x^2 - 4x - 8 really (4 +/- sqrt(48))/2?

    Because everytime I try working it out using the quadratic formula, my answer comes out with a 16 instead of the 4? ??
    Yes.

    x = \frac{-(-4) \pm \sqrt{(-4)^2 - 4(1)(-8)}}{2} = \frac{4 \pm \sqrt{16 + 32}}{2} = \frac{4 \pm \sqrt{48}}{2}

    Note:  = \frac{4 \pm \sqrt{16 \times 3}}{2} = \frac{4 \pm 4 \sqrt{3}}{2} = 2 \pm 2 \sqrt{3}.
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