SOLUTION: form a third-degree polynomial function with real coefficients such that 3+i and -9 are zeros

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Question 1055572: form a third-degree polynomial function with real coefficients such that 3+i and -9 are zeros
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Polynomials with real coefficients always have complex roots in complex conjugate pairs so,
f%28x%29=%28x-%283%2Bi%29%29%28x-%283-i%29%29%28x%2B9%29
f%28x%29=+%28x%5E2-6x%2B10%29%28x%2B9%29
f%28x%29=x%5E3%2B3x%5E2-44x%2B90