Hey there!
f(x) = (x + 3)^3
y = (x + 3)^3
y = (x + 3)(x + 3)(x + 3)
y = x(x^2) + x(6x) + x(9) + 3(x^2) + 3(6x) + 3(9)
y = x(x^2) + 6x(x) + 9(x) + 3(x^2) + 3(6x) + 3(9)
y = x^3 + 6x^2 + 9x + 3x^2 + 18x + 27
y = x^3 + 9x + 27x + 27
Therefore, your answer should be approximately: f(x) = x^3 + 9x + 27x + 27
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)