Question

Verify the Identity (a+b)whole cube =a cube+b cube+3ab(a+b)

Answer 1

(a + b)^3 = (a + b)(a + b)(a + b) 
                 = (a^2 + 2ab + b^2)(a + b) 
                 = a^3 + 3a^2b + 3ab^2 + b^3
                 = a^3 + 3ab(a+b) + b^3

Answer 2

follow above pic.

therefore this identity is proved....