Question 222298: Hello,
I am stumped on the following question. Appreciate the help.
Solve x^3-4x^2-2x+20=0 over the set of complex numbers. Answer by solver91311(24713) (Show Source):
Start with the rational root theorem. The possible rational roots are all where is an integer factor of the constant term and is an integer factor of the high-order term. That means that the possible rational roots for:
are
Next you need to use synthetic division to determine which of the 12 possible rational zeros are actually zeros. If you need a tutorial on synthetic division, Purplemath has a very good one at http://www.purplemath.com/modules/synthdiv.htm
I'm going to take a shortcut here and tell you that -2 is a zero, hence is a factor of and dividing by leaves a quotient of
So now we have
Leaving us with having to solve
which does not factor so we need to use the quadratic formula
