Question

Factorise the following:

x³ – 5x² – 4x + 20

Answer 1

Given: x³ – 5x² – 4x + 20

We know that,

= (x³ – 5x²) + (– 4x + 20)

Hence,

⇒ x²(x – 5) – 4(x – 5)

⇒ (x – 5) (x² – 4)

⇒ x² – 4 = (x + 2) (x – 2)

⇒ (x – 5) (x + 2) (x – 2)