Answer:
see explanation
Step-by-step explanation:
If a polynomial has roots x = a, x = b, x = c then
(x - a), (x - b) and (x - c) are the factors of the polynomial.
Note that complex roots occur in conjugate pairs, thus
x = - i is a root then so is x = i
given f(x) has roots
x = - 9, x = 7 and x = - i, x = i, then
(x + 9), (x - 7), (x + i), (x - i) are the factors of f(x)
