Part 1: the function would be
h(t)= -16t^2+15t+6.5
Part 2: using the same steps it stated on the calculator
x=1.26
Part 3: by using t= -b/(2a) 15 as b and -16 as a makes it
t= 15/32
Part 4: You then put 15/32 in for t in the equation making the maximum height
10.02
IDK IF THIS IS RIGHT BUT IVE SPENT ALL DAY ON THIS