Question

Помогите пожалуйста 6,7,8

Answer 1

Номер 6
а)
$\frac{18}{5 \sqrt{2} } = \frac{18 \sqrt{2} }{5 \sqrt{2 \sqrt{2} } } = \frac{18 \sqrt{2} }{5 \times 2} = \frac{9 \sqrt{2} }{5}$
б)
$\frac{15}{ \sqrt{13} - 2 \sqrt{2} } = \frac{15 \times ( \sqrt{13} + 2 \sqrt{2} ) }{13 - 4 \times 2} = \frac{15 \times ( \sqrt{13} + 2 \sqrt{2} ) }{5} = 3 \sqrt{13 + 6 \sqrt{2} }$
Номер 7:
а)
$\frac{ {x}^{2} - 10 }{x - \sqrt{10} } = \frac{( {x}^{2} - 10) \times (x + \sqrt{10)} }{ {x}^{2} - 10 } = x + \sqrt{10}$

б)
$\frac{8 - x}{ \sqrt{x} + 2 \sqrt{2} } = \frac{ - (x - 8) \times ( \sqrt{x} - 2 \sqrt{2} )}{x - 8} = - ( \sqrt{x} - 2 \sqrt{2} ) = - \sqrt{x} + 2 \sqrt{2}$
в)
$\frac{ \sqrt{75} - \sqrt{175} }{ \sqrt{28} - \sqrt{12} } = \frac{5 \sqrt{3} - 5 \sqrt{7} }{2 \sqrt{7} - 2 \sqrt{3} } = - \frac{5}{2}$