\[7x³ - 63x = 0\]
\[7x\left( x^{2} - 9 \right) = 0\]
\[7x(x + 3)(x - 3) = 0\]
\[x = 0\ \ или\ \ x = - 3\ \ или\ \ \ x = 3\]
\[Ответ:x = 0;\ \ x = \pm 3.\]