Respuesta :

This is a vertical parab because the directrix is horiz.  It opens down, because the directrix is above the focus.  The vertex is (0,0), half way between the focus and the directrix.  Thus, p = -5.    Let's use this info

4py = x^2

Here, 4(-5)y = x^2, or -20y = x^2, or y = (-1/20)x^2