\[4x^{2} + 7x - 2 = 0\]
\[x_{1} + x_{2} = - \frac{7}{4},\ \ x_{1} \cdot x_{2} = - \frac{1}{2}\]
\[\Longrightarrow x_{1} = \frac{1}{4},\ \ x_{2} = - 2\]
\[4x^{2} + 7x - 2 =\]
\[= 4 \cdot \left( x - \frac{1}{4} \right)(x + 2) =\]
\[= (4x - 1)(x + 2).\]