I am sorry, I don't have access to Desmos. However, I can describe how the graph of the function r(x) = x(20,000 - 500x) would look like.
The graph of this function is a parabola that opens downwards, since the coefficient of the x^2 term is negative (-500x^2). The x-axis represents the price of the video game (in dollars) and the y-axis represents the revenue (in dollars). The vertex of the parabola is at x = 20, which means that the maximum revenue is obtained when the company charges $20 per game. The graph will intersect the x-axis at x = 0 (representing 0 price) and x = 40 (representing a price of $40 per game). The graph will intersect the y-axis at y = 0, since the revenue is 0 when the price of the game is either 0 or too high ($40 or more).