Rút gọn (với các biêu thức đã có nghĩa )
a)\(\dfrac{m\sqrt{m}-y\sqrt{y}}{\sqrt{m}-\sqrt{y}}-\dfrac{m\sqrt{y}+y\sqrt{m}}{\sqrt{m}+\sqrt{y}}\)
b)\(\left(\dfrac{b\sqrt{b}+1}{\sqrt{b}+1}\right):\dfrac{b-1}{\sqrt{b}-1}\)
c)\(\left[\dfrac{\left(\sqrt{x}+\sqrt{y}\right)^2-4\sqrt{xy}}{x-\sqrt{xy}}-2\right].\dfrac{\sqrt{x^3}-y\sqrt{x}}{\sqrt{x}+\sqrt{y}}\)
d)\(\left(\dfrac{a\sqrt{a}-m\sqrt{m}}{\sqrt{a}-\sqrt{m}}+\sqrt{am}\right).\left(\dfrac{\sqrt{a}-\sqrt{m}}{a-m}\right)^2\)
\(\text{a},=\dfrac{\sqrt{m^3}-\sqrt{y^3}}{\sqrt{m}-\sqrt{y}}-\dfrac{\sqrt{my}\left(\sqrt{m}+\sqrt{y}\right)}{\sqrt{m}+\sqrt{y}}=m+\sqrt{my}+y-\sqrt{my}=m+y\\ b,=\left(\dfrac{\sqrt{b^3}+1}{\sqrt{b}+1}\right).\dfrac{\sqrt{b}-1}{b-1}=\left(b-\sqrt{b}+1\right).\left(\dfrac{1}{\sqrt{b}+1}\right)=\dfrac{b-\sqrt{b}+1}{\sqrt{b}+1}\)
đk a , m > 0 , y> 0
đk b b > 0
