Identify the focus and directrix of the parabola whose equation is .
(1 point)
focus: ; directrix:
focus: ; directrix:
focus: ; directrix:
focus: ; directrix:

To identify the focus and directrix of the given parabola, we start with the equation . This can be rewritten in standard form, indicating that it opens to the left since the coefficient of is negative.

The vertex of the parabola is at the point . For parabolas in the form , we see that , which means . The focus, located units from the vertex, is then at , and the directrix, being a vertical line units to the right of the vertex, is given by or .

So, the focus is at and the directrix is .

Thus, the correct choice is:
focus: ; directrix: .