\[\boxed{\text{124.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]
\[y = 2x²\]
\[\textbf{а)}\ y = 50:\ \]
\[2x^{2} = 50,\ \]
\[\ x^{2} = 25,\ \]
\[\ x = \pm 5\]
\[(5;50);( - 5;50) \Longrightarrow\]
\[\Longrightarrow точки\ пересечения.\]
\[\textbf{б)}\ y = 100:\]
\[2x^{2} = 100,\ \]
\[\ x^{2} = 50,\ \]
\[\ x = \pm \sqrt{50} = \pm 5\sqrt{2}\]
\[\left( 5\sqrt{2};100 \right);\left( - 5\sqrt{2};100 \right) \Longrightarrow\]
\[\Longrightarrow точки\ пересечения.\]
\[\textbf{в)}\ \]
\[2x^{2} = - 8,\ \ \]
\[x^{2} = - 4 \Longrightarrow\]
\[\Longrightarrow графики\ не\ пересекаются;\]
\[\textbf{г)}\ 2x² = 14x - 20\]
\[2x^{2} - 14x + 20 = 0\]
\[x^{2} - 7x + 10 = 0\]
\[D = 7^{2} - 4 \cdot 10 = 49 - 40 = 9\]
\[x_{1,2} = \frac{7 \pm 3}{2} = 5;2.\]
\[y(5) = 14 \cdot 5 - 20 = 70 - 20 =\]
\[= 50;\]
\[y(2) = 14 \cdot 2 - 20 = 28 - 20 =\]
\[= 8;\]
\[(5;50);\ \ (2;8) -\]
\[точки\ пересечения.\]