\[\frac{3}{x - 3} - \frac{x + 15}{x^{2} - 9} - \frac{2}{x} =\]
\[= \frac{3^{\backslash x(x + 3)}}{x - 3} - \frac{x + 15^{\backslash x}}{(x - 3)(x + 3)} - \frac{2^{\backslash x^{2} - 9}}{x} =\]
\[= \frac{3 \cdot (x + 3) \cdot x - x(x + 15) - 2 \cdot \left( x^{2} - 9 \right)}{x(x - 3)(x + 3)} =\]
\[= \frac{3x^{2} + 9x - x^{2} - 15x - 2x^{2} + 18}{x(x - 3)(x + 3)} =\]
\[= \frac{18 - 6x}{x(x - 3)(x + 3)} =\]