\[x^{2} - 7|x| + 12 = 0\]
\[1)\ x > 0:\]
\[x^{2} - 7x + 12 = 0\]
\[x_{1} + x_{2} = 7;\ \ \ x_{1} \cdot x_{2} = 12\]
\[x_{1} = 3;\ \ x_{2} = 4.\]
\[2)\ x < 0:\]
\[x^{2} + 7x + 12 = 0\]
\[x_{1} + x_{2} = - 7;\ \ \ x_{1} \cdot x_{2} = 12\]
\[x_{1} = - 4;\ \ x_{2} = - 3.\ \]
\[Ответ:x = \pm 3;\ \ x = \pm 4.\]