The minimum height occurs at the vertex of the parabola, which is at [tex](60,8)[/tex], so this height would be [tex]8[/tex].
The maximum height occurs at the bridge supports. Since [tex]x[/tex] represents the distance *from* the supports, this height occurs when [tex]x=0[/tex], which gives [tex]y=0.005(0-60)^2+8=26[/tex].