Question 1175927
The vertex is at (500, 10)
500 units sold 10 million dollar revenue, since written in vertex form.
{{{graph(300,300,-300,1500,-300000,500,-(x-500)^2+10)}}}

can expand this to R(x)=-x^2+1000x-249990
vertex is -b/2a=1000/2=500.

The point is that you can look at the problem and write the answer without expanding the formula. The vertex is the maximum for a negative quadratic, and vertex form gives you both the x and y values.