Tính (frac{3}{{2x + 3}} - frac{{x - 3}}{{2{x^2} + 3x}})

* Hướng dẫn giải

\(\begin{array}{l}
\frac{3}{{2x + 3}} - \frac{{x - 3}}{{2{x^2} + 3x}} = \frac{3}{{2x + 3}} - \frac{{x - 3}}{{x\left( {2x + 3} \right)}}\\
 = \frac{{3x - \left( {x - 3} \right)}}{{x\left( {2x + 3} \right)}} = \frac{{2x + 3}}{{x(2x + 3)}} = \frac{1}{x}
\end{array}\)