Answer:x equals 4
Step-by-step explanation:
To calculate the velocity, we use the given expression above which is <span>s(t) = −16t^2 + 144. First, we calculate the time it takes to reach the ground. Then, differentiate the expression and substitute time to the differentiated expression.
</span>s(t) = −16t^2 + 144
0 = -16t^2 + 144
t = 3
s'(t) = v = -32t
v = -32(3)
v = -96
Note: negative sign signifies that the object is going down
Vertex form is

where (h,k) is the vertex.
We can see that the vertex of the graph is at (2,0), and that the graph opens downwards, but does not look stretched at all.
Therefore,
a = -1
h = 2
k = 0
and our vertex form equation is

which is answer A