Question

Write the equation for the graphed function. I worked out y = 5 - 4 (x + 4)^2 but that isn't right. Any help would be appreciated.

Answer 1

Vertex form for a parabola with vertex (p,q) is

`y = a(x-p)^2 + q`

We have (p,q)=(-4,5) and another point (-3,2) so we can solve for a:

`2 = a(-3 - -4)^2 + 5`

`2 = a + 5`

`a = -3`

Putting it together,

Answer:
`y = -3(x + 4)^2 + 5`

We could multiply that out if we like but I won't bother.