Answer:
R(x) = -0.05x^2 +80x
Explanation:
Given the two points (x, p), the equation for the price associated with a given demand quantity can be written using the 2-point form:
p = (p2 -p1)/(x2 -x1)(x -x1) +p1
p = (40 -50)/(800 -600)(x -600) +50
p = -0.05x +80 . . . . simplify
Then the revenue equation is ...
R(x) = xp
R(x) = -0.05x^2 +80x