Final answer:
If a polynomial function f has a zero at x = -3, x - 3 is a factor of f(x).
Step-by-step explanation:
If a polynomial function f has a zero at x = -3, the statement that must be true is c) x - 3 is a factor of f(x).
- To determine if x - 3 is a factor of f(x), we can use synthetic division. Divide f(x) by x - 3 and if the remainder is zero, then x - 3 is a factor of f(x).
- For example, if f(x) = x^2 - 5x + 6, when we divide by x - 3, we get a remainder of zero. Therefore, x - 3 is a factor of f(x).