2. tìm x
a, \(3\sqrt{2x}\) + \(\sqrt{8x}\) - \(\sqrt{18x}\)= 16
b, \(\sqrt{4x+20}\) - \(3\sqrt{x+5}\) + \(\dfrac{4}{3}\) \(\sqrt{9x+45}\) = 6

1. rút gọn
g, \(\sqrt{54a}\)+ \(\sqrt{16a}\)+ \(\sqrt{49a}\)      (a>0)
m, \(\dfrac{20}{3+\sqrt{5}+\sqrt{2+2\sqrt{5}}}\)