Question

СРОЧНО ПОМОГИТЕ!!ДАЮ 20 БАЛЛОВ

Answer 1

Решение на прикреплённой фотографии

Answer 2

а) $\frac{4}{\sqrt{11}} = \frac{4}{\sqrt{11}} * \frac{\sqrt{11}}{\sqrt{11}} = \frac{4\sqrt{11}}{11}$

б) $\frac{\sqrt{5}}{\sqrt{5}-2} = \frac{\sqrt{5}}{\sqrt{5}-2} * \frac{\sqrt{5}-2}{\sqrt{5}-2} = \frac{5-2\sqrt{5}}{5-4\sqrt{5}+4} = \frac{5-2\sqrt{5}}{9-4\sqrt{5}} = \frac{5-2\sqrt{5}}{9-4\sqrt{5}} * \frac{9 + 4\sqrt{5}}{9 + 4\sqrt{5}} =\\= \frac{5+2\sqrt{5}}{1} = 5+2\sqrt{5}$

в) $\frac{9}{7+4\sqrt{3}} = \frac{9}{7+4\sqrt{3}} * \frac{7-4\sqrt{3}}{7-4\sqrt{3}} = \frac{9(7 - 4 \sqrt{3})}{1} = 63 - 36 \sqrt{3}$