1. RÚT GỌN BIỂU THỨC
a. \(\frac{\sqrt{a}+a\sqrt{b}-\sqrt{b}-b\sqrt{a}}{ab-1}\)
b. \(\frac{x+\sqrt{xy}}{y+\sqrt{xy}}\)
c. \(\frac{\sqrt{15}-\sqrt{6}}{\sqrt{35}-\sqrt{14}}\)
d. \(\frac{2\sqrt{15}-2\sqrt{10}+\sqrt{6}-3}{2\sqrt{5}-2\sqrt{10}-\sqrt{3}+\sqrt{6}}\)
e. \(\frac{-3\sqrt{3}+3}{2\sqrt{3}-2}\)