\[3x^{2} + 2x - 1 = 0\]
\[x_{1} + x_{2} = - \frac{2}{3}\]
\[x_{1} \cdot x_{2} = - \frac{1}{3}\]
\[\Longrightarrow x_{1} = - 1;\ \ x_{2} = \frac{1}{3}.\]
\[3x^{2} + 2x - 1 =\]
\[= 3 \cdot (x + 1)\left( x - \frac{1}{3} \right) =\]
\[= (x + 1)(3x - 1).\]
\[7x - 3x^{2} - 2 = 0\]
\[3x^{2} - 7x + 2 = 0\]
\[x_{1} + x_{2} = \frac{7}{3}\]
\[x_{1} \cdot x_{2} = \frac{2}{3}\]
\[\Longrightarrow x_{1} = 2;\ x_{2} = \frac{1}{3}.\]
\[7x - 3x^{2} - 2 =\]
\[= - 3 \cdot (x - 2)\left( x - \frac{1}{3} \right) =\]
\[= (2 - x)(3x - 1).\]