1,so sánh:
\(\dfrac{15}{\sqrt{6}+1}+\dfrac{4}{\sqrt{6}-2}va\dfrac{12}{3-\sqrt{6}}+\sqrt{6}\)
2.trục căn thức ở mẫu:
a. A=\(\dfrac{\sqrt{a+3}+\sqrt{a-3}}{\sqrt{a+3}-\sqrt{a-3}}\)
b.B=\(\dfrac{\sqrt{2}}{1+\sqrt{2}-\sqrt{3}}\)
3, rút gọn
A=\(\dfrac{\sqrt{2}+1}{\sqrt{2}-1}-\dfrac{\sqrt{2}-2}{1-\sqrt{2}}\)
B=\(\dfrac{\left(a\sqrt{b}+b\right)\left(\sqrt{a}+\sqrt{b}\right)}{a-b}.\sqrt{\dfrac{ab+b^2-2\sqrt{ab^3}}{a\left(a+2\sqrt{b}\right)+b}}\)
C=\(\dfrac{x^2+\sqrt{x}}{x-\sqrt{x}+1}-\dfrac{2x+\sqrt{x}}{\sqrt{x}}+1\)