Answer :
Answer:
y = -0.1x^2
Step-by-step explanation:
Start out with vertex form
y = a(x - h)^2 + k
The vertex at the origin
Therefor (h, k) = (0, 0)
y = ax^2
use point (20, -40) to find a
-40 = a(20^2)
-40 = a(400)
Divide both sides by
400
-0.1 = a
Therefor
y = -0.1x^2
This is standard form with a = -.01 and both b and c equal to zero