5) 5√(27t) − 4√(48t) − 2√(12t)

При \(t\geq0\):

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

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

Ответ: \(-5\sqrt{3t}\), \(t\geq0\).