Question

Очень важно!!! Помогите плиз

Answer 1

Ответ:

$1) \frac{a - 4}{\sqrt a - 2} = \frac{(\sqrt{a}-2)(\sqrt{a} +2)}{\sqrt a - 2} = \sqrt a + 2\\\\2) \frac{\sqrt{23}-23}{\sqrt{23}} = \frac{(\sqrt{23}-23)\cdot \sqrt{23}}{23} = \frac{23-23\sqrt{23}}{23} = 1 - \sqrt{23}\\\\3) \frac{a-5}{a+2\sqrt{5a}+5} = \frac{(\sqrt{a}-\sqrt{5})(\sqrt{a}+\sqrt{5})}{(\sqrt{a}+\sqrt{5})(\sqrt{a}+\sqrt{5})}}} = \frac{\sqrt{a}-\sqrt{5}}{\sqrt{a}+\sqrt{5}}$