Question

Write an equation of a parabola with a vertex at the origin and a directrix at y=5

Answer 1

The standard form is , where the focus is (h,k + p)
vertex at the origin and a directrix at y = 5. p = -5 (focus is (0,-5)
x^2 = -20y OR y = (-1/20)x^2

Answer 2

The answer is:

$y=-\frac{1}{20}x^2$