`~rai~`
\(\dfrac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\\=\dfrac{2\sqrt{4.2}-\sqrt{4.3}}{\sqrt{9.2}-\sqrt{16.3}}-\dfrac{\sqrt{5}+\sqrt{27}}{\sqrt{5}.\sqrt{6}+\sqrt{27}.\sqrt{6}}\\=\dfrac{4\sqrt{2}-2\sqrt{3}}{3\sqrt{2}-4\sqrt{3}}-\dfrac{5+\sqrt{27}}{\sqrt{6}(\sqrt{5}+\sqrt{27})}\\=\dfrac{-\sqrt{2}(\sqrt{6}-4)}{\sqrt{3}(\sqrt{6}-4)}-\dfrac{1}{\sqrt{6}}\\=\dfrac{-\sqrt{6}}{3}-\dfrac{\sqrt{6}}{2}\\=\dfrac{-2\sqrt{6}-\sqrt{6}}{6}\\=\dfrac{-3\sqrt{6}}{6}\\=-\dfrac{\sqrt{6}}{2}.\)
