Final answer:
The quadratic function for the Sydney Harbor Bridge arch is y = ax^2 + bx + c. The x-intercepts represent points where the bridge is level with the water surface.
Step-by-step explanation:
To model the arch of the Sydney Harbor Bridge, we can use a quadratic function of the form y = ax^2 + bx + c. The x-intercepts of the function represent the points where the arch is at the same height as the water. In the context of the bridge problem, the x-intercepts represent the points where the bridge is level with the water surface.