Question

-36y=x^2 The directrix of the parabola is:

Answer 1

Its actually y=9

Explanation:

Answer 2

Here, the equation of parabola is: (-36y)=x^2
The standard form of parabola is:

(X-h)^2=4p(y-k).
According to given equation, vertex = (0,0) and p = -9
This a vertical parabola opening down, because p = -9 here.
Therefore ditectrix will be y= -9