Polynomial Identities

Question

Does anybody know where i can find the properties below?

(a+b)^3
(a+b)^4

Answer

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

and,
( a + b ) ^4 = a^4 + 4 a^3b + 6 a^2 b^2 + 4 ab^3 + b^4