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PhoenixFire
Factoring a cubic polynomial. \[x^3-108x^2+3564x-34992\] I haven't needed to factor a cubic in a while and have forgotten how. Any help? I know the answers, just can't get them.
I know how to factor, but explaining it to someone is complicated. I haven't factored in so long either. I'll try to explain it. Sorry if I'm no help.. :/
http://answers.yahoo.com/question/index?qid=20080417160912AAt8IHC This could help :)
Sorry I can't help you. >_< I'm a failed Amby on my first day. :c
\[\begin{array}{l} {x^3} - 108{x^2} + 3564x - 34992 \\ = x({x^2} - 108x + 2916) + 648(x - 54) \\ = x{(x - 54)^2} + 648(x - 54) \\ = (x - 54)({x^2} - 54x + 648) \\ = (x - 54)(x - 36)(x - 18) \\ \end{array}\]
@drawar from where did you 2916?
I know but it is not found in the original equation.
Yes but you have to bring it in, and subtract it later, that's the one and only trick when doing factorization of polynomials.
Where did you subtract it? And in which course did you take this?
I don't remember which course, I think it's common sense, no?
Can you please explain the before the last step? I don't get it, how did you reach to that point?
Use a calculator to get 2 roots