10. \(5\sqrt{27t}-4\sqrt{48t}-2\sqrt{12t}\)

При \(t\ge 0\): \(\sqrt{27t}=3\sqrt{3t}\), \(\sqrt{48t}=4\sqrt{3t}\), \(\sqrt{12t}=2\sqrt{3t}\).

\(5\cdot3\sqrt{3t}-4\cdot4\sqrt{3t}-2\cdot2\sqrt{3t}=15\sqrt{3t}-16\sqrt{3t}-4\sqrt{3t}=-5\sqrt{3t}\).

Ответ: \(-5\sqrt{3t}\), при \(t\ge 0\).