Answer:
y = -1/2 ( x − 4 )^2 + 8
Explanation:
First find the vertex form
y = a ( x − h )^ 2 + k where ( h,k) is the vertex
The vertex is ( 4,8)
y = a ( x − 4 )^2 + 8
Now we need to determine a
Pick a point on the graph (0,0)
and substitute this point into the equation
0 = a ( 0 − 4 )^2 + 8
0 = a (16) +8
-8 = 16a
-8/16 =a
-1/2
y = -1/2 ( x − 4 )^2 + 8