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