Question

решите,пожалуйста!!!!

Answer 1

$\frac{1}{2\sqrt{5} } = \frac{\sqrt{5}}{2(\sqrt{5})^{2} } = \frac{\sqrt{5}}{2*5} = \frac{\sqrt{5}}{10} = 0,1\sqrt{5}\\\frac{8}{\sqrt{7} - 1} = \frac{8(\sqrt{7} + 1)}{(\sqrt{7} - 1)(\sqrt{7} + 1)} = \frac{8\sqrt{7} + 8 }{7-1} = \frac{8\sqrt{7} + 8 }{6} = \frac{4\sqrt{7} + 4 }{3}$