Решите примеры: а) √25000000 б) (2√7-3√7) / (6√7) в) 3√24+√54

а) $$√25000000 = 5000$$ б) $$\frac{2\sqrt{7}-3\sqrt{7}}{6\sqrt{7}} = \frac{-\sqrt{7}}{6\sqrt{7}} = -\frac{1}{6}$$ в) $$3\sqrt{24}+\sqrt{54} = 3\sqrt{4\cdot 6}+\sqrt{9\cdot 6} = 3\cdot 2\sqrt{6}+3\sqrt{6} = 6\sqrt{6}+3\sqrt{6} = 9\sqrt{6}$$