What is wrong with this question and how do you fix it

2. What are the vertex, focus, and directrix of the parabola with equation x=-3y^2?
This is a horizontal parabola. The vertex is at the origin and a=-3.

a=1 over 4c = -3
4c=1 over -3
c= -1/12

The focus is the point (0, -1/12). The directix is the line with equation x=1/12.

What is the error in this problem?

a < 0 so the parabola opens to the left.

The focus is not (0, -1/12).
Since the vertex is (0, 0) and the parabola opens to the left, the focus is (0-c, 0) = (-1/12, 0).

The process is fine.
You simply messed up writing the coodinates of the focus ... should be F(-1/12,0)

Have a good one!