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Math Help - basic help

  1. #1
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    basic help

    how to set 2x2-4x-1 eqaul to 0? do you have to factor it first or does it matter?
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  2. #2
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    Re: basic help

    Quote Originally Posted by pnfuller View Post
    how to set 2x2-4x-1 eqaul to 0? do you have to factor it first or does it matter?
    b^2-4ac is not a perfect square, so the expression will not factor over the rationals ... you'll have to complete the square or use the quadratic formula.
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  3. #3
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    Re: basic help

    do i need the whole quadratic formula or the just b^2-4ac part you mentioned?
    Quote Originally Posted by skeeter View Post
    b^2-4ac is not a perfect square, so the expression will not factor over the rationals ... you'll have to complete the square or use the quadratic formula.
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  4. #4
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    Re: basic help

    b^2-4ac is part of the quadratic formula ... and yes, you need the whole formula to solve for x.
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  5. #5
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    Re: basic help

    would the answers be 2.225 and -.225
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  6. #6
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    Re: basic help

    Quote Originally Posted by pnfuller View Post
    would the answers be 2.225 and -.225
    In fact they are. But all things considered I would suspect your instructor would prefer
    x = \frac{2 \pm \sqrt{6}}{2}

    -Dan
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