highest poit is the vertex
to find vertex
convert to vertex form or something
or use hax way
in form
y=ax²+bx+c
the x value of the vertex is -b/2a
the y value is found by subsituting -b/2a for x
h=-8t²+40t+0
x value of vertex is -40/(2*-8)=-40/-16=10/4=5/2
subsitute 5/2 for x
h=-8(5/2)²+40(5/2)
h=50
max height at 50 units
it take 5/2 or 2.5 seconds
ordered pair is (2.5,50) or (5/2,50)