Chapter 4 - 4.3 - Conics - 4.3 Exercises - Page 337: 19

Focus: $(0,p)=(0,-3)$ (Red line) Directrix: $y=3$ (Black line)

Parabola in the standard form with the vertex at origin (vertical axis): $x^2=4py$ $x^2+12y=0$ $x^2=-12y$ That is: $4py=-12y$ $p=-3$ $(0,p)=(0,-3)$ Directrix: $y=-p=3$