\[3x^{2} + 5x = 0\]
\[3x\left( x + \frac{5}{3} \right) = 0\]
\[x = 0;\ \ x = - \frac{5}{3} = - 1\frac{2}{3}.\]
\[Ответ:x = - 1\frac{2}{3};\ \ x = 0.\]