Задание 5. Найдите значение выражения: 1 (√20-√5)√5; 2 (√18-√2)/2; 3 (√48-√3)√3; 4 (√50+√2)/2; 5 (√45+√5)/5; 6 (√27+√3)√3; 7 √5·18·√10; 8 √7·12 - √21; 9 √2·45·√10; 10 √7·45·√35; 11 √11·32·√22; 12 √13·18·√26.

Определим предмет: Математика. 1) $$(\sqrt{20}-\sqrt{5})\cdot \sqrt{5} = \sqrt{20}\cdot \sqrt{5} - \sqrt{5}\cdot \sqrt{5} = \sqrt{100} - 5 = 10 - 5 = 5$$ 2) $$\frac{\sqrt{18}-\sqrt{2}}{2} = \frac{\sqrt{9\cdot 2}-\sqrt{2}}{2} = \frac{3\sqrt{2}-\sqrt{2}}{2} = \frac{2\sqrt{2}}{2} = \sqrt{2}$$ 3) $$(\sqrt{48}-\sqrt{3})\cdot \sqrt{3} = \sqrt{48}\cdot \sqrt{3} - \sqrt{3}\cdot \sqrt{3} = \sqrt{144} - 3 = 12 - 3 = 9$$ 4) $$\frac{\sqrt{50}+\sqrt{2}}{2} = \frac{\sqrt{25\cdot 2}+\sqrt{2}}{2} = \frac{5\sqrt{2}+\sqrt{2}}{2} = \frac{6\sqrt{2}}{2} = 3\sqrt{2}$$ 5) $$\frac{\sqrt{45}+\sqrt{5}}{5} = \frac{\sqrt{9\cdot 5}+\sqrt{5}}{5} = \frac{3\sqrt{5}+\sqrt{5}}{5} = \frac{4\sqrt{5}}{5}$$ 6) $$(\sqrt{27}+\sqrt{3})\cdot \sqrt{3} = \sqrt{27}\cdot \sqrt{3} + \sqrt{3}\cdot \sqrt{3} = \sqrt{81} + 3 = 9 + 3 = 12$$ 7) $$\sqrt{5 \cdot 18} \cdot \sqrt{10} = \sqrt{90} \cdot \sqrt{10} = \sqrt{900} = 30$$ 8) $$\sqrt{7 \cdot 12} - \sqrt{21} = \sqrt{84} - \sqrt{21} = \sqrt{4 \cdot 21} - \sqrt{21} = 2\sqrt{21} - \sqrt{21} = \sqrt{21}$$ 9) $$\sqrt{2 \cdot 45} \cdot \sqrt{10} = \sqrt{90} \cdot \sqrt{10} = \sqrt{900} = 30$$ 10) $$\sqrt{7 \cdot 45} \cdot \sqrt{35} = \sqrt{315} \cdot \sqrt{35} = \sqrt{11025} = 105$$ 11) $$\sqrt{11 \cdot 32} \cdot \sqrt{22} = \sqrt{352} \cdot \sqrt{22} = \sqrt{7744} = 88$$ 12) $$\sqrt{13 \cdot 18} \cdot \sqrt{26} = \sqrt{234} \cdot \sqrt{26} = \sqrt{6084} = 78$$