Expand (x + 3)^11 =
x^11 + 33 x^10 + 495 x^9 + 4455 x^8 + 26730 x^7 + 112266 x^6 + 336798 x^5 + 721710 x^4 + 1082565 x^3 + 1082565 x^2 + 649539 x + 177147
+600 By the binomial theorem, this term is \(\binom{11}{2}x^93^2=55*9x^9=495x^9\rightarrow\boxed{495}\)
