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Math Help - Can someone help me with this pre-Calculus question?

  1. #1
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    Can someone help me with this pre-Calculus question?

    If 2x2-dx+(31-d2)x+5 has a factor of x - d, what is the value of d if d is an integer?
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  2. #2
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    Re: Can someone help me with this pre-Calculus question?

    Let:

    f(x)=2x^2-dx+(31-d^2)x+5

    If f(x) has a factor of x-d then f(d)=0.

    Hint: use the rational roots theorem on the resulting cubic in d.
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  3. #3
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    Re: Can someone help me with this pre-Calculus question?

    post problems in the precalculus forum please.
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    Re: Can someone help me with this pre-Calculus question?

    so if f(d)=0 then then the new f(x) is 2x^2+31x+5??
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  5. #5
    MHF Contributor MarkFL's Avatar
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    Re: Can someone help me with this pre-Calculus question?

    No, that doesn't mean to let d = 0, that means when x = d, f(x) = 0.
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