$f(x)=-500x^{2}+25,000x$

The revenue $f(x)$, in dollars, that a company receives from sales of a product is given by the function $f$ above, where $x$ is the unit price, in dollars, of the product. The graph of $y=f(x)$ in the $xy$-plane intersects the $x$-axis at $0$ and $a$. What does $a$ represent?