a³ - 8 in the form of factors is :

1. (a - 2)(a² - 2a + 4)

2. (a - 2)(a² + 2a + 4)

3. (a - 2)(a² + 2a - 4)

4. (a + 2)(a² - 2a + 4)

27 + 8x³ in the form of factors is :

1. (3 + 2x)(9 + 6x + 4x²)

2. (3 - 2x)(9 + 6x + 4x²)

3. (3 + 2x)(9 - 6x + 4x²)

4. (3 - 2x)(9 - 6x + 4x²)

Factorise :

64 - a³b³