A bridge equation of the for h=ax^2+b where h is the height of the bridge in meters and x is the distance from the middle of the bridge in meters. The letters A and B are constants. When x=0, the bridge's height is 60 meters; and when the x=200, it's height is 0 meters.
How long is the bridge? Write an equation for the bridge's height. And how far from the center of the bridge are two points if the bridge's height at those points is 30 meters.