\[y = 3x^{2} - 1\ \ и\ y = 2x + 20\]
\[3x^{2} - 1 = 2x + 20\]
\[3x^{2} - 1 - 2x - 20 = 0\]
\[3x^{2} - 2x - 21 = 0\]
\[D = 1 + 63 = 64\]
\[x_{1} = \frac{1 + 8}{3} = \frac{9}{3} = 3;\]
\[x_{2} = \frac{1 - 8}{3} = - \frac{7}{3} = - 2\frac{1}{3}.\]
\[y_{1} = 2x + 20 = 2 \cdot 3 + 20 = 26;\]
\[y_{2} = 2 \cdot \left( - \frac{7}{3} \right) + 20 = - \frac{14}{3} + 20 =\]
\[= - 4\frac{2}{3} + 20 = 15\frac{1}{3}\]
\[Координаты\ точек\ пересечения\ графиков:\]
\[(3;26)\ и\ \left( - 2\frac{1}{3};15\frac{1}{3} \right).\]