We know that,

a³ - b³ = (a - b) (a² + a × b + b²)

Using this formula, we get

= 3a⁴b (a³ – 27b³)

= 3a⁴b [(a)³– (3b)³]

= 3a⁴b (a – 3b) [(a)² + a (3b) + (3b)²]

= 3a⁴b (a – 3b) (a² + 3ab + 9b²)