Answer:
y = (-1/80)x^2 +2x
Explanation:
The graph of the equation for the arch will go through the points ...
(0, 0), (160, 0), (80, 80)
We can start by making use of the zeros to write the function ...
y = a(x -0)(x -160)
To make the graph go through the point (80, 80), we must have ...
80 = a(80 -0)(80 -160) = (-80^2)a
-1/80 = a . . . . . . divide by the coefficient of "a"
So, our equation is ...
y = (-1/80)x(x -160)
y = (-1/80)x^2 +2x