\[x² + 7x = 0\]
\[x(x + 7) = 0\]
\[x = 0,\ \ x + 7 = 0\]
\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - 7\]
\[Ответ:x = 0;\ x = - 7.\]