If 4 is a root of f(x), which of the following is a factor of f(x)? (x+4)
neither (x+4) nor (x-4)
(x-4)
(x+4) and (x-4)

Given:

4 is a root of f(x).

To find:

A factor of f(x).

Solution:

We know that, if c is a root of a function f(x), then (x-c) is a factor of f(x).

In the given problem, 4 is a root of f(x).

So, we have c=4.

By using the above property we can say that, (x-4) is a factor of function f(x).

Since, (x-4) is a factor of function f(x), therefore, the correct option is C.

ok then what happened.

hello from mrbilldoesmath!

answer:   x (x+6)^2, choice b

discussion:

factor x out of the equation:

x^3 + 12x^2 + 36x = x (x^2 + 12x + 36).

note that 6+6 = 12 and 6*6 = 36 so the above factors into:

x (x+6)^2

which is choice b

you,

mrb