SOLUTION: Hi, How do you solve: x^3 - 2x^2 + 9x - 18 = 0 the teacher has given us one solution, 3i/square root of -9. i need two other solutions and am not sure how to obtain them

Question 344326: Hi,
How do you solve: x^3 - 2x^2 + 9x - 18 = 0
the teacher has given us one solution, 3i/square root of -9.
i need two other solutions and am not sure how to obtain them.
i have tried rational root theorem/ long division but do not know how to do it with square roots and imaginary numbers.
thanks
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Complex solutions always come in complex conjugate pairs.
So, if is a solution, then is also a solution.

You can then use polynomial long division to find the last root,
You can then get
Also, since only one root remains you know it must be real.
You could graph the equation and find it that way too.
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Looks like might be a number to stick in the function to see if .
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