Đáp án+Giải thích các bước giải:
`2) \frac{\sqrt{2}}{3 + 2\sqrt{2}} - \frac{6}{\sqrt{2}}`
`= \frac{\sqrt{2}}{3 + 2\sqrt{2}} - 3\sqrt{2}`
`= \frac{\sqrt{2} - 9\sqrt{2} - 12}{3 + 2\sqrt{2}}`
`= \frac{-8\sqrt{2} - 12}{3 + 2\sqrt{2}}`
`= \frac{-4(3 + 2\sqrt{2})}{3 + 2\sqrt{2}}`
`= - 4`
`3) \sqrt{\frac{2 + \sqrt{3}}{2}} - \frac{\sqrt{3}}{2}`
`= \frac{\sqrt{2 + \sqrt{3}}}{\sqrt{2}} - \frac{\sqrt{3}}{2}`
`= \frac{\sqrt{2} . \sqrt{2 + \sqrt{3}} - \sqrt{3}}{2}`
`= \frac{\sqrt{4 + 2\sqrt{3}} - \sqrt{3}}{2}`
`=\frac{\sqrt{(\sqrt{3} + 1)²} - \sqrt{3}}{2}`
`= \frac{\sqrt{3} + 1 - \sqrt{3}}{2}`
`= \frac{1}{2}`
