{y = -Sqrt[24964 - x^2] - 16/529 ArcCos[x/158]^2},-------------------

{y = Sqrt[24964 - x^2] - 16/529 ArcCos[x/158]^2}

x = 158.4cos(23)t ................(1)

y = 158.4sin(23)t – (16.1)(t^2)..............(2)

From (1)

t = x/158.4cos(23)

Substitute in (2)

y = 158.4sin(23) * x/158.4cos(23) - (16.1) ( x/158.4cos(23))^2

= x tan(23) - 16.1/[ 1/158.4cos(23)]^2 x^2

where a = - 16.1/[158.4cos(23)]^2, b = tan(23) c = 0