posted by Lynn .
I am trying to find the real coefficients of the given roots. Did I do this right?
Hmm.. I never done this before but I think you are right for the most part. You made a mistake on (x-3)(x+9)(x^2-6x-8) = 0. (x-3)^2 - 2i^2 does not expand to x^2-6x-8.
x-3)^2 - 2i^2
x^2 - 6x + 9 + 2
x^2 - 6x + 11