Question

упростите выражения: √5-√х/5-х; √7+а/а^2-7; 3√х-5/25-9х; 5х-6/√6-√5​

Answer 1

$1)\frac{\sqrt{5}-\sqrt{x}}{5-x}=\frac{\sqrt{5}-\sqrt{x}}{(\sqrt{5})^{2}-(\sqrt{x})^{2}}=\frac{\sqrt{5}-\sqrt{x}}{(\sqrt{5}-\sqrt{x})(\sqrt{5}+\sqrt{x})}=\frac{1}{\sqrt{5}+\sqrt{x}}$

$2)\frac{\sqrt{7}+a}{a^{2}-7}=\frac{\sqrt{7} +a}{a^{2}-(\sqrt{7})^{2}}=\frac{\sqrt{7}+a}{(a-\sqrt{7})(a+\sqrt{7})}=\frac{1}{a-\sqrt{7}}$

$3)\frac{3\sqrt{x}-5 }{25-9x}=\frac{3\sqrt{x}-5}{5^{2}-(3\sqrt{x})^{2}}=\frac{3\sqrt{x}-5}{(5-3\sqrt{x})(5+3\sqrt{x})}=-\frac{1}{5+3\sqrt{x}}$

4) неверно записано