\[\boxed{\mathbf{684\ (684).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \left| x^{2} + 7x - 4 \right| = 4\]
\[x^{2} + 7x - 4 = 4\]
\[4)\ x² + \frac{4x^{2}}{|x|} - 12 = 0\]
\[\boxed{\mathbf{6}\mathbf{8}\mathbf{4}\mathbf{\text{.\ }}Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ x² - 3|x| = 0\]
\[Ответ:x = 0;x = 3;\ x = - 3.\]
\[2)\ x² + |x| - 2x = 0\]
\[Ответ:x = 0;x = 1.\]
\[3)\ x² - \frac{|x|}{x} = 0\]
\[4)\ x² - \frac{2x^{2}}{|x|} = 0\]
\[Ответ:x = 2;\ x = - 2.\]