[tex]\displaystyle \\
6x(3x + 1) = 0 \\ \\
\Longrightarrow ~~ 6x = 0~~\texttt{or}~~3x+1=0 \\ \\
6x = 0 ~~\Longrightarrow ~~ x_1 = \frac{0}{6} = \boxed{0} \\ \\
3x+1 = 0 ~~\Longrightarrow ~~ 3x = -1 ~~\Longrightarrow ~~ x_2 = \frac{-1}{3} = \boxed{-\frac{1}{3}} \\ \\ [/tex]