College Algebra, Chapter 8, 8.1, Section 8.1, Problem 2

The equation $x^2 = 4py$ is a parabola with focus $F(\underline{0}, \underline{P} )$ and directrix $y = \underline{-P}$. So the graph of $x^2 = 12y$ is a parabola with focus $F(\underline{0}, \underline{3})$ and dicetrix $y = \underline{-3}$.