## Algebra 2 (1st Edition)

$R(x)=(28000-2000x)(11+x)=-2000(x-14)(11+x)$. The zeros of $R(x)$ are $14$ and $-11$, thus the average of them is $1.5$, so to maximize the revenue, each subscription should cost $11+1.5=12.5$. Then the revenue is $25000\cdot12.5=312500$