Đáp án:
`B = (sqrtx -sqrty)/sqrt(xy)`
Giải thích các bước giải:
`B= (sqrtx -sqrty)/(xysqrt(xy))[(1/x +1/y) xx 1/(x+y+2sqrt(xy)) +2/(sqrt(y)+sqrt(x))^3 xx (1/sqrt(x) +1/sqrt(y))]`
$B= \dfrac{\sqrt{x}-\sqrt{y}}{xy\sqrt{xy}} ÷ (\dfrac{y+x}{xy} \times \dfrac{1}{x+y+2\sqrt{xy}} +\dfrac{2}{(\sqrt{y}+\sqrt{x})^3} \times\dfrac{\sqrt{y}+\sqrt{x}}{\sqrt{xy}})\\B = \dfrac{\sqrt{x}-\sqrt{y}}{xy\sqrt{xy}}÷ (\dfrac{y+x}{xy(x+y+2\sqrt{xy})}+\dfrac{2}{(\sqrt{y}+\sqrt{x})^2} \times \dfrac{1}{\sqrt{xy}})\\B = \dfrac{\sqrt{x}-\sqrt{y}}{xy\sqrt{xy}} ÷ (\dfrac{y+x}{xy\times (\sqrt{x}+\sqrt{y})^2} +\dfrac{2}{(\sqrt{y}+\sqrt{x})^2 \times \sqrt{xy}})\\B = \dfrac{\sqrt{x}-\sqrt{y}}{xy\sqrt{xy}} \times \dfrac{xy\sqrt{xy}(\sqrt{x}+\sqrt{y})^2}{\sqrt{xy}\times y +\sqrt{xy} \times x + 2xy}\\B= (\sqrt{x}-\sqrt{y} \times \dfrac{(\sqrt{x}+\sqrt{y})^2}{\sqrt{xy}(y+x+2\sqrt{xy})}\\B = (\sqrt{x}-\sqrt{y})\times \dfrac{(\sqrt{x}+\sqrt{y})^2}{\sqrt{xy}(\sqrt{y}+\sqrt{x})^2}\\B = (\sqrt{x}-\sqrt{y})\times \dfrac{1}{\sqrt{xy}}\\B=\dfrac{\sqrt{x}-\sqrt{y}}{\sqrt{xy}}$
