\[\frac{1}{x^{2} - 3x + 3} + \frac{2}{x^{2} - 3x + 4} =\]
\[= \frac{6}{x^{2} - 3x + 5}\ \]
\[Пусть\ t = x^{2} - 3x + 3:\]
\[- 3t^{2} + t + 2 = 0\]
\[3t^{2} - t - 2 = 0\]
\[t_{1} + t_{2} = \frac{1}{3}\]
\[t_{1} \cdot t_{2} = - \frac{2}{3}\]
\[\Longrightarrow t_{1} = 1,\ \ t_{2} = - \frac{2}{3}.\]
\[Ответ:x = 2;x = 1.\]