What is the equation of a parabola with a focus of (8, –4) and a directrix of y = 2?

Answers available in ...
10Take this time to do your
best on this question.
A)
y = -1
3
(x - 8)2 - 1
B)
y = -1
3
(x + 8)2 - 1
C)
y = -1
12
(x - 8)2 - 1
D)
y = -1
12
(x + 8)2 - 1

Question

What is the equation of a parabola with a focus of (8, –4) and a directrix of y = 2?  

Answers available in ...
10Take this time to do your
best on this question.  
  A)
 y = -1 
3 
(x - 8)2 - 1  
  B)
 y = -1 
3 
(x + 8)2 - 1  
  C)
 y = -1 
12 
(x - 8)2 - 1  
  D)
 y = -1 
12 
(x + 8)2 - 1

mathmale · Answer

I'd suggest that you sketch this parabola.
Next, determine the distance from the focus to the directrix.
Locate the vertex and mark it with the proper coordinates.
Next, determine the distance from the focus to the vertex.

anonymous · Answer

Thanks!!