Đáp án+Giải thích các bước giải:
`a) \frac{\sqrt{70} - \sqrt{30}}{\sqrt{35} - \sqrt{15}}`
`= \frac{\sqrt{10}(\sqrt{7} - \sqrt{3})}{\sqrt{5}(\sqrt{7} - \sqrt{3})}`
`= \frac{\sqrt{10}}{\sqrt{5}}`
`= \sqrt{2}`
`r) \frac{9 - 2\sqrt{3}}{3\sqrt{6} - 2\sqrt{2}}`
`= \frac{\sqrt{3}(3\sqrt{3} - 2)}{\sqrt{2}(3\sqrt{3} - 2)}`
`= \frac{\sqrt{3}}{\sqrt{2}}`
`= \frac{\sqrt{6}}{2}`
`o) \frac{\sqrt{15} - 5}{\sqrt{6} - \sqrt{10}}`
`= \frac{\sqrt{5}(\sqrt{3} - \sqrt{5})}{\sqrt{2}(\sqrt{3} - \sqrt{5})}`
`= \frac{\sqrt{5}}{\sqrt{2}}`
`= \frac{\sqrt{10}}{2}`
`n) \frac{2\sqrt{3} + 3\sqrt{2} - \sqrt{6}}{2 + \sqrt{6} - \sqrt{2}}`
`= \frac{\sqrt{6}(\sqrt{2} + \sqrt{3} - 1)}{\sqrt{2}(\sqrt{2} + \sqrt{3} - 1)}`
`= \frac{\sqrt{6}}{\sqrt{2}}`
`= \sqrt{3}`
`B) \frac{2\sqrt{10} - 5}{4 - \sqrt{10}}`
`= \frac{\sqrt{5}(2\sqrt{2} - \sqrt{5})}{\sqrt{2}(2\sqrt{2} - \sqrt{5})}`
`= \frac{\sqrt{5}}{\sqrt{2}}`
`= \frac{\sqrt{10}}{2}`
`e) \frac{(\sqrt{10} - 1)² - 3}{\sqrt{10} + \sqrt{3} - 1}`
`= \frac{(\sqrt{10} - 1 - \sqrt{3})(\sqrt{10} - 1 + \sqrt{3})}{\sqrt{10} + \sqrt{3} - 1}`
`= \sqrt{10} - 1 - \sqrt{3}`
