Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
\frac{x}{{xy - 2{y^2}}} - \frac{2}{{{x^2} + x - 2xy - 2y}}\left( {1 + \frac{{3x + {x^2}}}{{3 + x}}} \right)\\
= \frac{x}{{y\left( {x - 2y} \right)}} - \frac{2}{{x\left( {x + 1} \right) - 2y\left( {x + 1} \right)}}.\left( {1 + \frac{{x\left( {x + 3} \right)}}{{3 + x}}} \right)\\
= \frac{x}{{y\left( {x - 2y} \right)}} - \frac{2}{{\left( {x - 2y} \right)\left( {x + 1} \right)}}\left( {1 + x} \right)\\
= \frac{x}{{y\left( {x - 2y} \right)}} - \frac{2}{{x - 2y}}\\
= \frac{{x - 2y}}{{y\left( {x - 2y} \right)}}\\
= \frac{1}{y}
\end{array}\)
