Question

друзья помогите пожалуйста​

Answer 1

Ответ:

Объяснение:

4.

$\frac{5}{3\sqrt{10} } = \frac{5 * \sqrt{10} }{3 *\sqrt{10} \sqrt{10} } =\frac{5 *\sqrt{10} }{3 * 10} =\frac{\sqrt{10}}{3 *2} =\frac{\sqrt{10}}{6}$

$\frac{8}{\sqrt{6} +\sqrt{2}} =\frac{8 * (\sqrt{6} -\sqrt{2} )}{(\sqrt{6} +\sqrt{2} )(\sqrt{6} -\sqrt{2} )} =\frac{8(\sqrt{6} -\sqrt{2} )}{(\sqrt{6} )^{2} - (\sqrt{2} )^{2} } =\frac{8(\sqrt{6} -\sqrt{2} )}{6 - 2} = \frac{8(\sqrt{6} -\sqrt{2} )}{4} =2(\sqrt{6} -\sqrt{2} )$

5.

$2\sqrt{2} +\sqrt{50} -\sqrt{98} = 2\sqrt{2} +\sqrt{25*2} -\sqrt{49*2} = 2\sqrt{2} +5\sqrt{2} -7\sqrt{2} = 0$

$5\sqrt{2} +2\sqrt{32} -\sqrt{98} =5\sqrt{2} +2\sqrt{16 *2} -\sqrt{49*2}=5\sqrt{2} +2*4\sqrt{2} -7\sqrt{2}=5\sqrt{2} +8\sqrt{2} -7\sqrt{2} =6\sqrt{2}$