If (x + 8) is a factor of f(x), which of the following must be true?

a) x = –8 and x = 8 are roots of f(x).
b) neither x = –8 nor x = 8 is a root of f(x).
c) f(–8) = 0
d) f(8) = 0

Since (x + 8) is a factor of f (x) then the following equation is fulfilled when f (x) = 0:

From here, we clear the value of x:

Then, when evaluating the function for x = -8 it is fulfilled that:

Therefore, x = -8 is a root of the function f (x).

the following must be true:

C)