Question 1131808
maximum height is vertex and occurs at t=-b/2a, the formula for the vertex of a quadratic.
This is -96/-32 or 3 seconds ANSWER for b.
h(3)=-144+288+256=400 feet ANSWER

c. changing all signs, 16t^2-96t-256=0
divide by 16, t^2-6t-16=0
(t-8)(t+2)=0
t=8 seconds, only positive root ANSWER.

{{{graph(300,300,-10,10,-100,500,-16x^2+96x+256)}}}