Answer:
x(x - 4)(x + 1)
Explanation:
x³ - 3x² - 4x ← factor out x from each term
= x(x² - 3x - 4) ← factor the quadratic
consider the factors of the constant term (- 4) which sum to give the coefficient of the x- term (- 3)
the required factors are - 4 and + 1 , since
- 4 × + 1 = - 4 and - 4 + 1 = - 3 , then
x²- 3x - 4 = (x - 4)(x + 1)
and
x³ - 3x² - 4x = x(x - 4)(x + 1)