\[x² - 4x - 3 = 0\ \]
\[D = b^{2} - 4ac =\]
\[= 16 - 4 \cdot 1 \cdot ( - 3) =\]
\[= 16 + 12 = 28\]
\[x_{1} = \frac{4 + 2\sqrt{7}}{2} = 2 + \sqrt{7} = 4,646\]
\[x_{2} = \frac{4 - 2\sqrt{7}}{2} = 2 - \sqrt{7} =\]
\[= - 0,646\]
\[Ответ:x_{1} = 4,646;\ \ x_{2} =\]
\[= - 0,646.\]