$\begin{array}{1 1} \frac{-1}{18(2+3x^3)^2}+c. \\ \frac{1}{18(2+3x^3)^3}+c. \\ \frac{-1}{18(2+3x^3)^3}+c. \\ \large \frac{1}{9(2+3x^3)^2}+c.\end{array}$