Radical Expression

$\left ( \sqrt{48} - 3\sqrt{27} \right) ÷ \sqrt{3}=\left (\sqrt{3 \times 4^2}-3 \sqrt {3 \times 3^2} \right) ÷ \sqrt{3}$

$\cdots=\left (4 \times \sqrt{3}-9 \times \sqrt{3} \right) ÷\sqrt{3} =4-9=\boxed{\boxed{-5}}$