Đáp án+Giải thích các bước giải:
`a) \frac{2\sqrt{2} - 4}{4 - \sqrt{2}}`
`= \frac{2\sqrt{2}(1 - \sqrt{2})}{\sqrt{2}(2\sqrt{2} - 1)}`
`= \frac{2\sqrt{2}(1 - \sqrt{2})}{\sqrt{2}(\sqrt{2} - 1)(2 + \sqrt{2} + 1)}`
`= \frac{-2}{3 + \sqrt{2}}`
`= \frac{2(3 - \sqrt{2})}{7}`
`= \frac{6 - 2\sqrt{2}}{7}`
`b) \frac{\sqrt{10} - \sqrt{2}}{\sqrt{5} - 2} + \frac{2 - \sqrt{2}}{1 - \sqrt{2}}`
`= \frac{(\sqrt{10} - \sqrt{2})(\sqrt{5} + 2)}{5 - 4} + \frac{\sqrt{2}(\sqrt{2} - 1)}{1 - \sqrt{2}}`
`= \sqrt{50} + 2\sqrt{10} - \sqrt{10} - 2\sqrt{2} - \sqrt{2}`
`= \sqrt{10} + 2\sqrt{2}`
