An auditorium has seats for 1,400 people. Tickets to attend a show at the auditorium currently cost S6 .00Eor each $1 .00 increase to the ticket price,100 fewer tickets will be sold. This situation can be modeled by the equation y=-100x²+800x+8,400, where x represents the increase in ticket price, in dollars, and represents the revenue,in dollars, from ticket sales. It this equation is graphed in the xy-plane,at what value of x is the maximum of the graph?