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Math Help - Brain Teaser

  1. #1
    Senior Member sakonpure6's Avatar
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    Brain Teaser

    A cubic function may be expressed as ax^3 + bx^2 + cx +d =0 or as (x-x1)(x-x2)(x-x3)=0 where x1,x2,x3 are the roots of the equation. Use this fact to find the values of(x1+x2+x3). (x1x2 + x1x3 +x2x3) and (x1x2x3) in terms of a,b,c, and d
    I have no idea what to do... enlighten me if you can , please and thank you.
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  2. #2
    MHF Contributor
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    Re: Brain Teaser

    Multiply through the second representation and equate coefficients of equal powers of x in both representations. Assume that the leading coefficient a is 1 in the first representation.

    For further info, this has to do with Vieta's formulas.
    Thanks from sakonpure6 and topsquark
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