\[y = 3x - 200;\ \ \ \ \ y = - 4x + 500\]
\[3x - 200 = - 4x + 500\]
\[3x + 4x = 500 + 200\]
\[7x = 700\]
\[x = 100.\]
\[y = 3 \bullet 100 - 200 =\]
\[= 300 - 200 = 100.\]
\[Ответ:(100;100).\]