h = -5t^2 +5t + 10
a) t = 0, h = 10 at time 0
b) h = (-5t + 10) ( t + 1)
c) put 0 in for the height and set each factor = to 0 and solve each
0 = (-5t + 10) and 0 = (t + 1)
solve each t = 2 and t = -1, so t = 2 sec is your solution
d) because a parabola is symmetric, the max will be half way between -1 and 2, at t = 1/2
h = -5(1/2)^2 +5(1/2) + 10
h = -5(1/4) + 5/2 +10
h = -5/4 + 5/2 + 10
h = -5/4 + 10/4 + 40/4
h = 45/4