f(x)=(x+1)(x+2)(x−4)

Explanation:

f(x) = x^3 - x^2 - 10x - 8.

We find out that

f(-1) = -1 -1 + 10 - 8 = 0,

then, one factor is (x + 1).

After division -->

f(x)=(x+1)(x2−2x−8)

The trinomial in parentheses can be factored.

Find 2 numbers knowing sum (-2) and product (-8).

They are (2) and (-4)

(x2−2x−8)=(x+2)(x−4)

f(x)=(x+1)(x+2)(x−4)