1] rút gọn
a) (\(\sqrt{12}\) + \(3\sqrt{5}\) - \(4\sqrt{135}\)) 13
b) \(\sqrt{252}\) - \(\sqrt{700}\) + \(\sqrt{1008}\) - \(\sqrt{448}\)
c) \(2\sqrt{40\sqrt{12}}\) - \(2\sqrt{\sqrt{75}}\) -\(3\sqrt{5\sqrt{48}}\)
2]
a) A= \(\frac{\sqrt{6}+\sqrt{14}}{2\sqrt{3}+\sqrt{28}}\)
b) B= \(\frac{9\sqrt{5}+3\sqrt{27}}{\sqrt{5}+\sqrt{3}}\)
c) C= \(\frac{3\sqrt{8}-2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}\)