\[4x² + x - 5 = 0\]
\[D = 1 + 80 = 81\]
\[x_{1} = \frac{- 1 + 9}{8} = 1;\ \ \ \]
\[x_{2} = \frac{- 1 - 9}{8} = - \frac{10}{8} = - \frac{5}{4}.\]
\[4x^{2} + x - 5 =\]
\[= 4 \cdot (x - 1)\left( x + \frac{5}{4} \right) =\]
\[= (x - 1)(4x + 5).\]