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Math·Advanced Math·Nonlinear functions

hard

An auditorium has seats for $2,600$ people. Tickets to attend a show at the auditorium currently cost $8.00. For each $1.00 increase to the ticket price, $100$ fewer tickets will be sold. This situation can be modeled by the equation $y=-100x^2+1,800x+20,800$, where $x$ represents the increase in ticket price, in dollars, and $y$ represents the revenue, in dollars, from ticket sales. If this equation is graphed in the $xy$-plane, at what value of $x$ is the maximum of the graph?

A

$8$

B

$9$

C

$18$

D

$26$