\[3x^{2} + 3x - 6 =\]
\[= 3 \cdot (x + 2)(x - 1)\]
\[x^{2} + x - 2 = 0\]
\[x_{1} + x_{2} = - 1;\ \ x_{1} \cdot x_{2} = - 2\]
\[x_{1} = - 2;\ \ x_{2} = 1.\]