\[5x + 10x^{2} = 0\]
\[5x(1 + 2x) = 0\]
\[1)\ 5x = 0\]
\[x = 0.\]
\[2)\ 1 + 2x = 0\]
\[2x = - 1\]
\[x = - 0,5.\]
\[Ответ:x = - 0,5;x = 0.\]