Question

Q23.Find the value of a^3 − 27b^3 + 45ab + 125, when a = 3b − 5.

Answer 1

Answer:

Maybe the value is wrong

Answer 2

Step-by-step explanation:

a³ − 27b³ + 45ab + 125

a = 3b - 5

putting the value of a in the equation

(3b - 5)³ - 27b³ + 45ab + 125

Using identify (a − b)³ = a³ − b³− 3a b ( a − b )

[(3b)³ - (5)³ - 3×3b×5 (3b - 5)] - 27b³ + 45ab + 125

[27a³ - 135 - 45b(3b - 5)] - 27b³ + 45ab + 125

27a³ - 135 - 135b² + 225b - 27b³ + 45ab + 125

27a³ - 27b³ - 135b² + 45ab + 10