\[4x^{2} = 4 \cdot (4x + 1) - x\]
\[4x^{2} = 16x + 4 - x\]
\[4x^{2} - 15x - 4 = 0\]
\[D = 225 + 64 = 289\]
\[x_{1} = \frac{15 + 17}{8} = \frac{32}{8} = 4;\]
\[x_{2} = \frac{15 - 17}{8} = - \frac{2}{8} = - \frac{1}{4} = - 0,25.\]
\[Ответ:\ - 0,25;\ \ 4.\]