8.Найдите значение выражения \sqrt{4^4}.

8. $\sqrt{4^4} = 4^2 = 16$ 9. $\sqrt{7 \cdot 12} \cdot \sqrt{21} = \sqrt{7 \cdot 4 \cdot 3 \cdot 3 \cdot 7} = \sqrt{7^2 \cdot 3^2 \cdot 2^2} = 7 \cdot 3 \cdot 2 = 42$ 10. $\sqrt{2 \cdot 45} \cdot \sqrt{10} = \sqrt{90} \cdot \sqrt{10} = \sqrt{900} = 30$ 11. $\frac{72}{(2\sqrt{3})^2} = \frac{72}{4 \cdot 3} = \frac{72}{12} = 6$ 12. $\frac{200}{(5\sqrt{2})^2} = \frac{200}{25 \cdot 2} = \frac{200}{50} = 4$ 13. $\frac{220}{(2\sqrt{5})^2} = \frac{220}{4 \cdot 5} = \frac{220}{20} = 11$ 14. $(\sqrt{18} + \sqrt{2}) \cdot \sqrt{2} = \sqrt{36} + \sqrt{4} = 6 + 2 = 8$ 15. $\frac{\sqrt{21} \cdot \sqrt{14}}{\sqrt{6}} = \sqrt{\frac{21 \cdot 14}{6}} = \sqrt{\frac{294}{6}} = \sqrt{49} = 7$ 16. $\frac{\sqrt{65} \cdot \sqrt{13}}{\sqrt{5}} = \sqrt{\frac{65 \cdot 13}{5}} = \sqrt{13 \cdot 13} = 13$ 17. $\frac{\sqrt{75} \cdot \sqrt{10}}{\sqrt{30}} = \sqrt{\frac{750}{30}} = \sqrt{25} = 5$ 18. $(\sqrt{11} + 3)^2 - 6\sqrt{11} = 11 + 6\sqrt{11} + 9 - 6\sqrt{11} = 20$ 19. $(\sqrt{5} + 9)^2 - 18\sqrt{5} = 5 + 18\sqrt{5} + 81 - 18\sqrt{5} = 86$ 20. $(\sqrt{19} + 2)^2 - 4\sqrt{19} = 19 + 4\sqrt{19} + 4 - 4\sqrt{19} = 23$ 21. $\frac{(4\sqrt{3})^2}{60} = \frac{16 \cdot 3}{60} = \frac{48}{60} = 0,8$ 22. $\frac{(2\sqrt{5})^2}{160} = \frac{4 \cdot 5}{160} = \frac{20}{160} = 0,125$ 23. $\frac{(3\sqrt{5})^2}{75} = \frac{9 \cdot 5}{75} = \frac{45}{75} = 0,6$