Question

Решите 2✓20-3✓45+3✓80-✓125
Дам 30б​

Answer 1

$\displaystyle\bf\\2\sqrt{20} +3\sqrt{45} +3\sqrt{80} -\sqrt{125} =\\\\\\=2\sqrt{4\cdot 5} +3\sqrt{9\cdot 5} -\sqrt{25\cdot 5} =\\\\\\=2\sqrt{2^{2} \cdot 5} +3\sqrt{3^{2} \cdot 5} -\sqrt{5^{2} \cdot 5} =\\\\\\=2\cdot 2\sqrt{5} +3\cdot 3\sqrt{5} -5\sqrt{5} =\\\\\\=4\sqrt{5} +9\sqrt{5} -5\sqrt{5} =8\sqrt{5}$