Đáp án:
1) \(\dfrac{{2\sqrt x }}{{x - y}}\)
Giải thích các bước giải:
\(\begin{array}{l}
1)A = \dfrac{{\left( {x - \sqrt {xy} + y} \right)}}{{x\sqrt x + y\sqrt y }} + \dfrac{{x + \sqrt {xy} + y}}{{x\sqrt x - y\sqrt y }}\\
= \dfrac{{x - \sqrt {xy} + y}}{{\left( {\sqrt x + \sqrt y } \right)\left( {x - \sqrt {xy} + y} \right)}} + \dfrac{{x + \sqrt {xy} + y}}{{\left( {\sqrt x - \sqrt y } \right)\left( {x + \sqrt {xy} + y} \right)}}\\
= \dfrac{1}{{\sqrt x + \sqrt y }} + \dfrac{1}{{\sqrt x - \sqrt y }} = \dfrac{{\sqrt x - \sqrt y + \sqrt x + \sqrt y }}{{x - y}}\\
= \dfrac{{2\sqrt x }}{{x - y}}\\
2)A = \dfrac{4}{{3\sqrt y }};B = \dfrac{x}{y}
\end{array}\)
