8a³ + 1 in the form of factors is :

1. (2a + 1)(4a² - 2a + 1)

2. (2a - 1)(4a² - 2a + 1)

3. (2a + 1)(4a² + 2a + 1)

4. (2a - 1)(4a² + 2a + 1)

$\Big(\dfrac{x^3}{8} - \dfrac{y^3}{27}\Big)$ in the form of factors is :

1. $\Big(\dfrac{x}{2} - \dfrac{y}{3}\Big)\Big(\dfrac{x^2}{4} - \dfrac{xy}{6} + \dfrac{y^2}{9}\Big)$

2. $\Big(\dfrac{x}{2} + \dfrac{y}{3}\Big)\Big(\dfrac{x^2}{4} - \dfrac{xy}{6} + \dfrac{y^2}{9}\Big)$

3. $\Big(\dfrac{x}{2} - \dfrac{y}{3}\Big)\Big(\dfrac{x^2}{4} + \dfrac{xy}{6} + \dfrac{y^2}{9}\Big)$

4. $\Big(\dfrac{x}{2} + \dfrac{y}{3}\Big)\Big(\dfrac{x^2}{4} + \dfrac{xy}{6} + \dfrac{y^2}{9}\Big)$

Factorise :

a⁶ + 27b³

Factorise :

3x⁷y - 81x⁴y⁴