\(\left(3\sqrt{18}+3\sqrt{15}-\sqrt{6}\right):\sqrt{3}\)
\(=\left(\sqrt{3}\cdot\sqrt{3}\cdot\sqrt{18}+\sqrt{3}\cdot\sqrt{3}\cdot\sqrt{15}-\sqrt{2}\cdot\sqrt{3}\right):\sqrt{3}\)
\(=\sqrt{3}\left(\sqrt{54}+\sqrt{45}-\sqrt{2}\right):\sqrt{3}\)
\(=\sqrt{54}+\sqrt{45}-\sqrt{2}\)