y= - 16t^2 + 414
factor out -2
y = -2 (8 t^2 -207)
set y=0
0 = -2 (8t^2 -207)
divide by -2
0 = (8t^2 -207)
add 207 to each side
207 = 8t^2
divide by 8
207/8 = t^2
take the sqrt of each side
sqrt(207/8) = t
t=5.087seconds
Answer: t=5.09 seconds to the nearest hundredth
y=-0.017x2+0.51x
y= -.017x(x-30)
one of the zero's is 30ft for the distance.
max = c - (b^2 / 4a)
max = -(.51)^2/4(-.017)=.2601/.068=3.825
