SOLUTION: Identify the equation of the parabola with its focus at (-4,9) and the directrix y=-3. A) 24(y-7)=(x+4)^2 B) -12(y+4)=(x+4)^2 C) 24(y-3)=(x+4)^2 D) 12(y-4)=(x+4)^2

Question 1039377: Identify the equation of the parabola with its focus at (-4,9) and the directrix y=-3.
A) 24(y-7)=(x+4)^2
B) -12(y+4)=(x+4)^2
C) 24(y-3)=(x+4)^2
D) 12(y-4)=(x+4)^2
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
You can use those pieces of information and the distance formula to derive the equation. A set of points (x,y) is the same distance from (-4,9) as from (x,-3). Put into the formula,

.
Simplify this.
First step after that initial equation could be

and keep going to whatever form of the equation you need for making a comparison to your choices.

Study this demonstration:
Equation of parabola given focus and directrix - Vertex not at the origin - video
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