Question

Write an equation of a parabola with a vertex at the origin and a directrix at y = 5.

Someone help please !
(PICTURE BELOW)

Answer 1

@satellite73 , @terenzreignz

Answer 2

you know it faces down so it must look like \(y=-ax^2\)

Answer 3

i know it's a negative answer

Answer 4

you can write it as \(-4py=x^2\) where \(p=5\) so you get \(-20y=x^2\) or
\[y=-\frac{1}{20}x^2\]

Answer 5

i got it. Thank you. my answer is c correct. i had it right

Answer 6

In general, @Kayy_Drizzyy
If your vertex is at a point (h , k)
Then your parabola would have the equation
(x-h)² =(+/-) 4p(y-k)
depending on where your parabola faces.

Answer 7

good
did you get the last one?

Answer 8

no. I'm skipping that for last @satellite73

Answer 9

the one with no right answers?

Answer 10

ok