Đáp án+Giải thích các bước giải:
`5) (\frac{3 - \sqrt{6}}{\sqrt{2} - \sqrt{3}} + 1)(\frac{\sqrt{21} + \sqrt{15}}{\sqrt{7} + \sqrt{5}} + 1)`
`= (\frac{\sqrt{3}(\sqrt{3} - \sqrt{2})}{\sqrt{2} - \sqrt{3}} + 1)(\frac{\sqrt{3}(\sqrt{7} + \sqrt{5})}{\sqrt{7} + \sqrt{5}} + 1)`
`= (-\sqrt{3} + 1)(\sqrt{3} + 1)`
`= 1 - 3`
`= -2`
`6) \frac{3\sqrt{2} + 2\sqrt{3}}{\sqrt{6}} - \sqrt{5 - 2\sqrt{6}}`
`= \frac{\sqrt{6}(\sqrt{3} + \sqrt{2})}{\sqrt{6}} - \sqrt{3 - 2\sqrt{6} + 2}`
`= \sqrt{3} + \sqrt{2} - \sqrt{(\sqrt{3} - \sqrt{2})²}`
`= \sqrt{3} + \sqrt{2} - \sqrt{3} + \sqrt{2}`
`= 2\sqrt{2}`
