\[3x² + \frac{x^{2}}{|x|} - 4 = 0\ \]
\[1)\ x > 0:\]
\[3x² + \frac{x^{2}}{x} - 4 = 0\ \]
\[3x^{2} + x - 4 = 0\]
\[D = b^{2} - 4ac =\]
\[= 1 - 4 \cdot 3 \cdot ( - 4) = 1 + 48 = 49\]
\[x_{1} = \frac{- 1 + 7}{6} = \frac{6}{6} = 1;\]
\[x_{2} = \frac{- 1 - 7}{6} = - \frac{8}{6} = - \frac{4}{3} =\]
\[= - 1\frac{1}{3} < 0\ (не\ подходит).\]
\[2)\ \ x < 0:\]
\[3x^{2} + \frac{x^{2}}{- x} - 4 = 0\]
\[3x² - x - 4 = 0\]
\[D = b^{2} - 4ac =\]
\[= 1 - 4 \cdot 3 \cdot ( - 4) = 1 + 48 =\]
\[= 49\]
\[x_{1} = \frac{1 + 7}{6} = \frac{8}{6} = \frac{4}{3} =\]
\[= 1\frac{1}{3} > 0\ (не\ подходит).\]
\[x_{2} = \frac{1 - 7}{6} = - \frac{6}{6} = - 1.\]
\[Ответ:x = 1;x = - 1.\]