Найдите значение выражения: $(\sqrt{20}-\sqrt{5})\sqrt{5}$

1. $(\sqrt{20}-\sqrt{5})\sqrt{5} = \sqrt{20}\cdot\sqrt{5} - \sqrt{5}\cdot\sqrt{5} = \sqrt{100} - \sqrt{25} = 10 - 5 = 5$ 2. $(\sqrt{18}-\sqrt{2})\sqrt{2} = \sqrt{18}\cdot\sqrt{2} - \sqrt{2}\cdot\sqrt{2} = \sqrt{36} - \sqrt{4} = 6 - 2 = 4$ 3. $(\sqrt{48}-\sqrt{3})\sqrt{3} = \sqrt{48}\cdot\sqrt{3} - \sqrt{3}\cdot\sqrt{3} = \sqrt{144} - \sqrt{9} = 12 - 3 = 9$ 4. $(\sqrt{50}+\sqrt{2})\sqrt{2} = \sqrt{50}\cdot\sqrt{2} + \sqrt{2}\cdot\sqrt{2} = \sqrt{100} + \sqrt{4} = 10 + 2 = 12$ 5. $(\sqrt{45}+\sqrt{5})\sqrt{5} = \sqrt{45}\cdot\sqrt{5} + \sqrt{5}\cdot\sqrt{5} = \sqrt{225} + \sqrt{25} = 15 + 5 = 20$ 6. $(\sqrt{27}+\sqrt{3})\sqrt{3} = \sqrt{27}\cdot\sqrt{3} + \sqrt{3}\cdot\sqrt{3} = \sqrt{81} + \sqrt{9} = 9 + 3 = 12$ 7. $\sqrt{5}\cdot 18\cdot\sqrt{10} = 18\sqrt{50} = 18\sqrt{25\cdot2} = 18\cdot 5\sqrt{2} = 90\sqrt{2}$ 8. $\sqrt{7}\cdot 12\cdot\sqrt{21} = 12\sqrt{7\cdot 21} = 12\sqrt{7\cdot 3\cdot 7} = 12\sqrt{49\cdot 3} = 12\cdot 7\sqrt{3} = 84\sqrt{3}$ 9. $\sqrt{2}\cdot 45\cdot\sqrt{10} = 45\sqrt{20} = 45\sqrt{4\cdot 5} = 45\cdot 2\sqrt{5} = 90\sqrt{5}$ 10. $\sqrt{7}\cdot 45\cdot\sqrt{35} = 45\sqrt{7\cdot 35} = 45\sqrt{7\cdot 5\cdot 7} = 45\sqrt{49\cdot 5} = 45\cdot 7\sqrt{5} = 315\sqrt{5}$ 11. $\sqrt{11}\cdot 32\cdot\sqrt{22} = 32\sqrt{11\cdot 22} = 32\sqrt{11\cdot 2\cdot 11} = 32\sqrt{121\cdot 2} = 32\cdot 11\sqrt{2} = 352\sqrt{2}$ 12. $\sqrt{13}\cdot 18\cdot\sqrt{26} = 18\sqrt{13\cdot 26} = 18\sqrt{13\cdot 2\cdot 13} = 18\sqrt{169\cdot 2} = 18\cdot 13\sqrt{2} = 234\sqrt{2}$ **Ответ:** 1. $5$ 2. $4$ 3. $9$ 4. $12$ 5. $20$ 6. $12$ 7. $90\sqrt{2}$ 8. $84\sqrt{3}$ 9. $90\sqrt{5}$ 10. $315\sqrt{5}$ 11. $352\sqrt{2}$ 12. $234\sqrt{2}$