Rút gọn biểu thức

a) \(\dfrac{9-a}{\sqrt{a}+3}-\dfrac{9-6\sqrt{a}+a}{\sqrt{a}-3}\)

b) \(\dfrac{a+b-2\sqrt{ab}}{\sqrt{a}-\sqrt{b}}-\dfrac{a-b}{\sqrt{a}+\sqrt{b}}\)

HELP ME

Rút gọn biểu thức

a) \(\dfrac{\left(\sqrt{a}-\sqrt{b}\right)^2+4\sqrt{ab}}{\left(\sqrt{a+\sqrt{b}}\right)^2-4\sqrt{ab}}.\dfrac{a-b}{\left(\sqrt{a}-\sqrt{b}\right)^2}\) \(\left(đkxđ:a\ne b;a\ge0;b\ge0\right)\)

b) \(\dfrac{a+b-2\sqrt{ab}}{\sqrt{a}-\sqrt{b}}-\dfrac{a-b}{\left(\sqrt{a}+\sqrt{b}\right)^2}\)\(\left(đkxđ:a\ne b;a\ge0;b\ge0\right)\)

HELP ME PLSSSSSSSSSS

Chứng minh
a) \(9+4\sqrt{5}=\left(\sqrt{5}+2\right)^2\)
b)\(\sqrt{9-4\sqrt{5}}-\sqrt{5}=-2\)

Help me plsssssss

thực hiện phép tính

\(\sqrt{\left(\sqrt{3}-2\right)^2}+\sqrt{\left(3-\sqrt{3}\right)^2}\)

Help me