Bài 1 : Rút gọn
a) \(\dfrac{2\sqrt{3}+2}{4\sqrt{3}+4}\) b) \(\dfrac{\sqrt{10}+\sqrt{15}}{\sqrt{8}+\sqrt{12}}\) c) \(\dfrac{\sqrt{2}+\sqrt{3}+\sqrt{6}+\sqrt{8}+\sqrt{16}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\) d) \(\sqrt{9+\sqrt{17}}\). \(\sqrt{9-\sqrt{17}}\)