Which of the following statements must be true about the polynomial function f(x)? If 1+ the sqrt of 13 is a root of f(x), then
-1- the sqrt of 13 is also a root of f(x). If 1 + 13i is a root of f(x), then 1 – 13i is also a root of f(x). If 13 is a root of f(x), then –13 is also a root of f(x). If –13 + i is a root of f(x), then 13 + i is also a root of f(x).
The correct answer is: if is a root of , then is also a root of .
In fact, every polynomial has real and/or complex solutions. If all solutions are real, we're good. But if not all of them are real, then the complex ones come in couple of conjugate solutions. Since and are conjugate complex numbers, if one of them is a solution, the other must be as well.