We will have vertex at (-1,2) and p = -3 (so the parabola will be "upside down").

The vertex is at (-1, 2), since we know the focal distance is | p | = 3.

math expression

We don't really need to find the equation, but as an exercise:

Using

(xh)2 = 4p(yk)

We have:

(x + 1)2 = 4(-3)(y − 2)

x2 + 2x + 1 = -12y + 24

12y = -x2 − 2x − 1 + 24

y = (-x2 − 2x + 23)/12