1: \(=\dfrac{-\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{y}-\sqrt{x}\right)}{\sqrt{y}-\sqrt{x}}=-\sqrt{x}-\sqrt{y}\)
2: \(=\dfrac{\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}{\left(\sqrt{x}-\sqrt{y}\right)\left(x+\sqrt{xy}+y\right)}=\dfrac{\sqrt{x}+\sqrt{y}}{x+\sqrt{xy}+y}\)
3: \(=x+\sqrt{xy}+y\)