Answer:
3x^2+36x+81
Step-by-step explanation:
(x+9)(3x+9)=3[tex]x^{2}[/tex] +9x+37x+81
⇛(x + 9) (3x + 9)
⇛x(3x+9) + 9(3x+9)
⇛3x² + 9x + 18x + 81
⇛3x² + 27x + 81
