\[\frac{x}{x - 3} - \frac{9}{x^{2} - 3x} = 0\]
\[\frac{x^{\backslash x}}{x - 3} - \frac{9}{x(x - 3)} = 0;\ \ \ \ x \neq 3;\ \ x \neq 0\]
\[x^{2} - 9 = 0\]
\[x^{2} = 9\]
\[x = 3\ (не\ подходит);\]
\[x = - 3\]
\[Ответ:x = - 3.\]