(×+3)³

Answer 1

(x+3) (x+3)^2 = (x+3) (x^2 + 6 x + 9)
= x * (x^2 + 6 x + 9) + 3 * (x^2 + 6 x + 9)
= x^3 + 6 x^2 + 9 x + 3 x^2 + 18 x + 27
= x^3 + 9 x^2 + 27 x + 27

Answer 2

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

in your case ... (x + 3)^3 = x^3 + 9 x^2 + 27 x + 27