Question

Пожалуйста помогите хотябы 3 первых задания!!!!! Даю 100 баллов!!!!!

Answer 1

1) $\frac{2}{5}\sqrt{75} + \sqrt{2}( \sqrt{2} - \sqrt{6} ) = 2\sqrt{3} + 2 -\sqrt{12} = 2 + 2\sqrt{3} - 2\sqrt{3} = 2$

2) a) $\frac{\sqrt{a} + 7 }{49 - a} = \frac{\sqrt{a} + 7 }{7^{2} - \sqrt{a}^{2} } = \frac{\sqrt{a} + 7 }{(7 - \sqrt{a} )(\sqrt{a} + 7 )} } = \frac{1}{7-\sqrt{a} }$

б) $\frac{2 + \sqrt{2} }{\sqrt{10} + \sqrt{5} } = \frac{\sqrt{2}(\sqrt{2} + 1)}{\sqrt{5}(\sqrt{2} + 1 )} = \sqrt{\frac{2}{5} } = \sqrt{\frac{4}{10} } = \frac{2}{\sqrt{10} }$

3) a) $\frac{63}{\sqrt{7} } = \frac{\sqrt{63} }{\sqrt{49}} = \sqrt{\frac{7*9}{7} } = 3$

б) $\frac{3}{\sqrt{15} + \sqrt{6} }} = \frac{3(\sqrt{15} - \sqrt{6} )}{15 - 6} = \frac{3(\sqrt{15} - \sqrt{6} )}{9} = \frac{(\sqrt{15} - \sqrt{6} )}{3}$