SOLUTION: Really need some help. Use the given zero to find the remaining zeros of the function. f(x)=x^3-9x^2+9x-81 zero: 3 i Enter the remaining zeros of f. Any help would be appr

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Really need some help. Use the given zero to find the remaining zeros of the function. f(x)=x^3-9x^2+9x-81 zero: 3 i Enter the remaining zeros of f. Any help would be appr      Log On


   



Question 767477: Really need some help. Use the given zero to find the remaining zeros of the function. f(x)=x^3-9x^2+9x-81 zero: 3 i
Enter the remaining zeros of f.

Any help would be appreciated.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


If is a zero of a polynomial function, then the conjugate, must also be a zero. That is because complex roots always come in conjugate pairs.

So if is a zero, must also be a zero. That means that both and must both be factors of the polynomial. The product of a pair of conjugates is the difference of two squares so:



Divide the original polynomial by using polynomial long division. The quotient will be the remaining factor from which solving for the remaining zero is trivial.

John

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