Which parabola?

Equation of the parabola
y - y1 = 4p(x - x1)
The Vertex of the parabola given is (0, 0) because it does not have the values of x1 and y1.
Then Vertex = (0,0)
-Look for two values of y to the left and two points to the right.
You can choose the points that you which
x y
-3 y = -(-3)^2 = -9
-1 y = -(-1)^2 = -1
0 y = -(0)^2 = 0
1 y = -(1)^2 = -1
3 y = -(3)^2 = -9
80% is the same as 4/5, so 4/5 of the class= 20. That means that if there was a picture, 4 parts would be shaded, and 1 would not. 1/4 of 20 is 5, so 1 part= 5 people. 5 x 5 = 25. 25 is the answer. :)
Answer:
A
Step-by-step explanation: