Question

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

Answer 1

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

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From here, we clear the value of x:

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

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

Answer:

the following must be true:

C)
`f (-8) = 0`

Answer 2

The answer to the question letter "C. f(-8) = 0". The factor x + 8 gives the value of x = -8. This means that neither A nor B is the answer to the question. Substituting also -8 to the value of x can give an answer of f(x) or f(-8) equal to zero.