\[\frac{x^{2} - x - 12}{x + 3} = 0\ \ \ \ \ \ \ \ \ \ \ x \neq - 3\]
\[x^{2} - x - 12 = 0\]
\[x_{1} = \frac{1 + \sqrt{49}}{2} = \frac{1 + 7}{2} = \frac{8}{2} = 4\]
\[x_{2} = \frac{1 - \sqrt{49}}{2} = \frac{1 - 7}{2} = \frac{- 6}{2} =\]
\[= - 3\ (не\ подходит).\]
\[Ответ:4.\]