Write the standard form equation of the parabola with focus at (0,−3) and vertex at the origin.

Answer 1

use x^2=4py

p is the distance from the focus to the vertex and from the vertex to the directrix

seeing that the focus is (0,-3) and the vertex is (0,0), the directrix must be above the vertex

therefore the parabola opens downward

the distance, p, from the vertex to the focus is -3

therefore the equation is x^2=4*(-3)*y

x^2=-12y

Answer 2

This is vertical parabola x² = 4py, where p = - 3. So equation of parabola x² = - 12y