(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 + (a + b) 2 + (2)²]

= (a + b – 2) [a² + b² + 2ab + 2 (a + b) + 4]