Answer:
729x^3 + 729x^2 + 243x + 27
Step-by-step explanation:
(9x+3)^3
(9x+3)(9x+3)(9x+3)
(81x^2 + 54x + 9)(9x+3)
(729x^3 + 486x^2 + 81x + 243x^2 + 162x + 27)
