Đáp án+Giải thích các bước giải:
`A=\frac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}`
`A=\frac{4-\sqrt{6}}{3-2\sqrt{6}}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}`
`A=\frac{-\sqrt{6}}{3}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}`
`A=\frac{-6\sqrt{5}-18\sqrt{3}-3\sqrt{5}-9\sqrt{3}}{3\sqrt{30}+27\sqrt{2}}`
`A=\frac{-9\sqrt{5}-27\sqrt{3}}{3\sqrt{30}+27\sqrt{2}}`
`A=\frac{-3\sqrt{3}(\sqrt{15}+9)}{3\sqrt{3}(\sqrt{10}+3\sqrt{6})}`
`A=\frac{-\sqrt{15}-9}{\sqrt{10}+3\sqrt{6}}`
`A=\frac{-22\sqrt{6}}{-44}`
`A=\frac{-\sqrt{6}}{2}`
