Question

simplify: (3a+5b)³ – (3a–5b)³​

Answer 1

ans

formula => (a³-b³)= (a-b)(a²-b²-2ab)

10b(27a²+25b²)

Answer 2

Answer:

Let us consider,

Here, a = 3a + 5b and b = 3a – 5b

By using the formula,

[a³ – b³ = (a – b) (a² + ab + b²)]

Let us simplify the given expression, we get

(3a + 5b)3 – (3a – 5b)3 = [(3a + 5b) – (3a – 5b)] [(3a + 5b)² + (3a + 5b) (3a – 5b) + (3a – 5b)²]

= (3a + 5b – 3a + 5b) [(9a² + 30ab + 25b²) + (9a² – 25b²) + (9a² – 30ab + 25b²)]

= 10b (9a² + 9a² + 9a² + 30ab – 30ab + 25b² – 25b² + 25b²)

= 10b (27a² + 25b²)

= 270a²b + 250b³