Question #5eda4

1 Answer
Sep 4, 2017

f(x) = x^3 - 3x^2 + x - 3

Explanation:

The complex conjugate root theorem states that if a+bi is a root of a polynomial, then so is a-bi. So, since i is a root, then -i will also be a root.

Since the polynomial has the zeros 3, i, and -i, the factors of the polynomial will be x-3, x-i, and x-(-i) = x + i.

f(x) = (x-3)(x-i)(x+i)

Since (a+b)(a-b) = a^2 - b^2, we can rewrite the function as

f(x) = (x-3)(x^2 - i^2)

f(x) = (x-3)(x^2 + 1)

We can expand this further.

f(x) = x^3 + x - 3x^2 - 3

In standard form, the function is f(x) = x^3 - 3x^2 + x - 3.