\[\boxed{\mathbf{527\ (527).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 7\sqrt{2} = \sqrt{49 \cdot 2} = \sqrt{98};\]
\[2)\ 3\sqrt{13} = \sqrt{9 \cdot 13} = \sqrt{117};\]
\[3) - 2\sqrt{17} = - \sqrt{4} \cdot \sqrt{17} = - \sqrt{68};\]
\[4) - 10\sqrt{14} = - \sqrt{1400};\]
\[5)\ 5\sqrt{8} = \sqrt{25 \cdot 8} = \sqrt{200};\]
\[6)\ 6\sqrt{a} = \sqrt{36a};\]
\[7)\frac{1}{4}\sqrt{32} = \sqrt{\frac{1}{16} \cdot 32} = \sqrt{2};\]
\[8) - \frac{2}{3}\sqrt{54} = - \sqrt{\frac{4}{9} \cdot 54} = - \sqrt{24};\]
\[9)\frac{1}{8}\sqrt{128a} = \sqrt{\frac{1}{64} \cdot 128a} = \sqrt{2a};\]
\[10) - 0,3\sqrt{10b} = - \sqrt{\frac{9}{100} \cdot 10b} =\]
\[= - \sqrt{0,9b};\]
\[11)\ 3\ \sqrt{\frac{1}{3}} = \sqrt{9 \cdot \frac{1}{3}} = \sqrt{3};\]
\[\ 12)\frac{2}{9}\sqrt{\frac{27}{28}} = \sqrt{\frac{4}{81} \cdot \frac{27}{28}} = \sqrt{\frac{1}{21}}.\]