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Math Help - NEED HELP ASAP Quartic factoring

  1. #1
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    Exclamation NEED HELP ASAP Quartic factoring

    hey everbody got an assignment from my math teacher today that me and the rest of the class are absolutly stumped on"

    f(x) = X^4 - 3x^3 - 13x^2 + 3X + 12
    f(-1) = 0

    Then i synthetically divided and came up with this unfinished division statement.

    Therefore: X^4 - 3x^3 - 13x^2 + 3X + 12
    = ( X + 1 ) ( X^3 - 4X^2 - 9X + 12)
    = ryguy272 totally stuck




    ANY HELP APPRECITATED ( i cant spell )
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  2. #2
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    Hello, ryguy272!

    f(x) \:=\: x^4 - 3x^3 - 13x^2 + 3x + 12

    f(-1) \,=\, 0
    Then i divided and came up with:
    . . x^4 - 3x^3 - 13x^2 + 3X + 12 \:=\:(x + 1)( x^3 - 4x^2 - 9x + 12)

    . . . totally stuck

    I guess you didn't notice that: f(1) = 0 . . . so (x-1) is also a factor.

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  3. #3
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    Whenever the coefficients add up to 0, you have 1 as a root. It's a quick tip when you're looking to drop a polynomial down a notch.
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