$\begin{align}  & \int{3\sqrt{x}dx}=3\int{{{x}^{\tfrac{1}{2}}}}dx=\frac{3({{x}^{\tfrac{1}{2}+1}})}{\tfrac{1}{2}+1}+C \\ & \int{3\sqrt{x}dx}=\frac{3{{x}^{\tfrac{3}{2}}}}{\tfrac{3}{2}}+C=2{{x}^{\tfrac{3}{2}}}+C \\\end{align}$