SOLUTION: n=3, 3 and 2i are zeros, f(-1)=-20

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Question 999226: n=3, 3 and 2i are zeros, f(-1)=-20
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
two roots are (x-3)^2
two more are (x^2+4), because if 2i is a root, so is -2i
a(x-3)^2(x^2+4)= polynomial
a(x^2-6x+9)(x^2+4)
a(x^4-6x^3+13x^2-24x+36)=0
When x=(-1), y=-20
a(1+6+13+24+36)=-20
a(80)=-20
a=(-1/4)
polynomial is
(-1/4)x^4+(3/2)x^3-(13/4)x^2+6x-9