Answer:
The vertex is at (2.75, 133)
Explanation:
y=-16t^2+88t+12
The x coordinate for the vertex is at the axis of symmetry
h = -b/2a
where at^2 +bt+c
a = -16, b= 88 and c = 12
h = -88/ (2*-16)
h = -88/-32
h =2.75
To find the y coordinate, we substitute this into the equation
y = -16(2.75)^2 +88(2.75) +12
y = -121+242+12
y = 133