We know that,

(a + b)³ = a³ + b³ + 3ab (a + b)

Using this formula, we get

= (a + b)³ – 8

= (a + b)³ – (2)³

We know that,

a³ - b³ = (a - b) (a² + a × b + b²)

Using this formula, we get

= (a + b – 2) [(a+ b)² + 2 (a + b) + 4)]