\[ОДЗ:\ x^{2} - x - 1
eq 0\]
\[D = ( - 1)^{2} - 4 \cdot 1 \cdot ( - 1) =\]
\[= 1 + 4 = 5\]
\[x_{1}
eq \frac{1 + \sqrt{5}}{2};\ \ x_{2}
eq \frac{1 - \sqrt{5}}{2}.\]
\[\left( x^{4} - 2x^{2} + 1 \right) - 7x\left( x^{2} - 1 \right) = 0\]
\[\left( x^{2} - 1 \right)^{2} - 7x\left( x^{2} - 1 \right) = 0\]
\[\left( x^{2} - 1 \right)\left( x^{2} - 1 - 7x \right) = 0\]
\[(x - 1)(x + 1)(x² - 7x - 1) = 0\]
\[x = 1;\ \ \ x = - 1.\ \ \]
\[x^{2} - 7x - 1 = 0\]
\[D = ( - 7)^{2} - 4 \cdot 1 \cdot ( - 1) =\]
\[= 49 + 4 = 53\]
\[x_{1} = \frac{7 + \sqrt{53}}{2};\ \ \ \ \ x_{2} = \frac{7 - \sqrt{53}}{2}.\]
\[Ответ:x = \pm 1;x = \frac{7 \pm \sqrt{53}}{2}\text{\ .}\]