\[ \frac{x}{x-3} - \frac{x^2 + 3x}{2x + 3} \cdot \left( \frac{x + 3}{x^2 - 3x} - \frac{x}{x^2 - 9} \right) \]

----- Nội dung ảnh -----
\[
\frac{x}{x-3} - \frac{x^2 + 3x}{2x + 3} \cdot \left( \frac{x + 3}{x^2 - 3x} - \frac{x}{x^2 - 9} \right)
\]