Question 978020
You are only interested in discussing the positive roots for P(x).    The roots of both signs are still useful for factorization of P.


Note, you want to start with {{{P(x)=x^4-x^3-11x^2+9x+18}}}.
... EXPONENTS!!!



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system got stuck and cutoff the rest of my message.


The function will be W shaped, but curved hump and valleys, not sharp.


{{{P(x)=(x+1)(x+3)(x-2)(x-3)}}}, the results of synthetic division and rational roots theorem.  There is a maximum between x=-1 and x=2, but you KNOW it must be between x=0 and x=2.