Question

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Answer 1

If a polynomial with real coefficients has complex roots, then the complex roots are pairs of complex conjugates. Since one of the given roots is 3 + 9i, you also must have 3 - 9i as a root.
That means you have 4 roots:
8, -14, 3 + 9i, and 3 - 9i

If the roots of a polynomial are a, b, c, and d, then the polynomial is
y = (x - a)(x - b)(x - c)(x - d)

Answer 2

so would it be f(x) = x4 - 58x2 + 1212x - 10,080 ? @mathstudent55

Answer 3

correct