If 5 + 6i is a root of the polynomial function f(x), which of the following must also be a root of f(x)?

5-6i

Step-by-step explanation:

The complex conjugate root theorem states that if (a+bi) is a root, then (a-bi) must also be a root and vice versa.

We know that (5+6i) is a root.

Then by the above theorem, (5-6i) must also be a root.

Hence, our solution is (5-6i).

i believe the answer is c.