\[x^{3} - 25x = 0\]
\[x\left( x^{2} - 25 \right) = 0\]
\[x(x + 5)(x - 5) = 0\]
\[x = 0;x = - 5;x = 5.\]
\[Ответ:x = 0;x = \pm 5.\]