Đáp án:
$\begin{array}{l}
MSC = 2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)\\
+ )\dfrac{7}{{2x}} = \dfrac{{7.\left( {x - 2y} \right)\left( {x + 2y} \right)}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
= \dfrac{{7.\left( {{x^2} - 4{y^2}} \right)}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
= \dfrac{{7{x^2} - 28{y^2}}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
+ )\dfrac{4}{{x - 2y}} = \dfrac{{4.2x.\left( {x + 2y} \right)}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
= \dfrac{{8{x^2} + 16xy}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
+ )\dfrac{{x - y}}{{8{y^2} - 2{x^2}}} = \dfrac{{ - \left( {x - y} \right).x}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}\\
= \dfrac{{xy - {x^2}}}{{2.x.\left( {x - 2y} \right)\left( {x + 2y} \right)}}
\end{array}$
