Factor by grouping x3−4x2−4x+16

To factor by grouping, we group the terms as follows:

(x^3 - 4x^2) + (-4x + 16)

Now, we factor out the greatest common factor from each group:
x^2(x - 4) - 4(x - 4)

Next, notice that we have a common binomial factor, (x - 4), which we can factor out:
(x^2 - 4)(x - 4)

(x^2 - 4) is a difference of squares and can be factored further:
(x + 2)(x - 2)

Therefore, the factored form of x^3 - 4x^2 - 4x + 16 is (x + 2)(x - 2)(x - 4).