Question

Bài 3 nha

Answer 1

a) \(Đkxđ:x>0;y>0;x\ne y.\)

b)

 \(A=\left(\sqrt{x}+\dfrac{y-\sqrt{xy}}{\sqrt{x}-\sqrt{y}}\right):\dfrac{x\sqrt{xy}+y\sqrt{xy}}{\sqrt{xy}\left(y-x\right)}.\\ A=\dfrac{x-\sqrt{xy}+y-\sqrt{xy}}{\sqrt{x}-\sqrt{y}}:\dfrac{\sqrt{xy}\left(x+y\right)}{\sqrt{xy}\left(y-x\right)}.\\ A=\dfrac{x+y}{\sqrt{x}-\sqrt{y}}.\dfrac{y-x}{x+y}.\\ A=\dfrac{y-x}{\sqrt{x}-\sqrt{y}}.\\ A=\dfrac{-\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}{\sqrt{x}-\sqrt{y}}.\\ A=-\sqrt{x}-\sqrt{y}.\)