Question

a^3-3a^2b+3ab^2-2b^3​

Answer 1

it is the expansion of (a-b)^3.

Answer 2

A^3-3A^2B+3AB^2-2B^3

-> A^3-3A^2B+3AB^2-B^3-B^3

-> (A-B)^3-B^3

-> (A-B-B) {(A-B)^2+(A-B)B+B^2}

-> (A-2B) (A^2-2AB+B^2+AB-B^2+B^2)

-> (A-2B)(A^2-AB+B^2)