Find the cube of:

2a + 3b

(2a + 3b)³

Using the formula,

(x + y)³ = x³ + y³ + 3x²y + 3xy²

= (2a)³ + (3b)³ + 3 $\times$ (2a)² $\times$ (3b) + 3 $\times$ (2a) $\times$ (3b)²

= 8a³ + 27b³ + 36a²b + 54ab²

Hence, (2a + 3b)³ = 8a³ + 27b³ + 36a²b + 54ab²