Вопрос:

Ответ:

\[y = - 2x^{2}\]

\[y = 40x:\]

\[- 2x^{2} = 40x\]

\[- 2x^{2} - 40x = 0\]

\[- 2x(x + 20) = 0\]

\[x = 0;\ \ \ x = - 20.\]

\[Ответ:(0;0);\ \ ( - 20;\ - 800).\]