What are the FOCI of the following graph?

Question

binary3i · Answer

no the answer is D
do you wana know why?

anonymous · Answer

you got the 3 and the 5 right?

anonymous · Answer

lets do them one at a time
@binary3i  is responding to the first one i will take the second

binary3i · Answer

fine.
b was the vertex 
but focus is the point 
from where the distance to any point on curve will also be equal to the distance betwen te point on curve and directrix.|dw:1354899754796:dw|
ab=bp

binary3i · Answer

yo @charlotteakina

anonymous · Answer

the vertices are $(0,4)$ and $(0,-4)$ so you know the $y^2$ term comes first, and it looks like 
$$\frac{y^2}{16}-\frac{x^2}{b^2}=1$$ you need $b^2$ 
the focus is at $(5,0)$ tells you $5^2=16+b^2$ and so $b^2=25-16=9$ 
your equation is 
$$\frac{y^2}{16}-\frac{x^2}{9}=1$$

anonymous · Answer

ok