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Math Help - How do I find the value of x?

  1. #1
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    question solved - not sure how to delete

    ---
    I'm not sure how to delete this question - I had an error in my calculations but I managed to figure it out and there's no point in keeping this question up anymore
    Last edited by misiaizeska; October 18th 2012 at 10:24 AM.
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  2. #2
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    Re: How do I find the value of x?

    You perhaps have multiplied or subtracted incorrectly. 2(x- 2)(x- 3)(x+ 5)= 2(x^2- 5x+ 6)(x+ 5) = 2(x^3-38x+ 30)= 2x^3- 38x+ 60= 120 so that 2x^3- 38x- 60= 0, not "- 150". Dividing through by 2, x^3- 19x- 30= 0. I notice that (-2)^3- 19(-2)- 30= -8+ 38- 30= 0.
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  3. #3
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    Re: How do I find the value of x?

    Yep, this is exactly what I got wrong! For some reason I though f(x) = 210 instead of 120, not sure why I got my numbers mixed up. Thank you though!
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