Which equation represents a parabola with the focus at (0, -1) and the directrix y
= 1?
(1) x2 = -8y
(3) x2 = Sy
(2) x2 = - 4y
(4) x2 = 4y

Step-by-step explanation:

The vertex is halfway between focus and directrix, at (0,0).

The equation has the form y = ax².

Focal length p = distance between focus and vertex = 1

p = 1/|4a|

1 = 1/|4a|

|a| = ¼

The focus lies below the vertex, so the parabola opens downwards and a<0.

y = -¼x²

the answer is b.

step-by-step explanation:

identity property is where 0+whatever number=whatever number. basically 0+ a number.

d

step-by-step explanation: