when it hits the ground, then h=0
find the xintercept or in this case the tintercepts
c=76
v=135
h=-16t^2+135t+76
use quadratic formula
ax^2+bx+c=0
x=\(\frac{-b+/- \sqrt{b^2-4ac} }{2a}\)
a=-16
b=135
c=76
x=\(\frac{-135+/- \sqrt{135^2-4(-16)(76)} }{2(-16)}\)
x=\(\frac{-135+/- \sqrt{18225+4864} }{-32}\)
x=\(\frac{-135+/- \sqrt{23089} }{-32}\)
aprox
x=-0.5297 or 8.967
exclude the negative root since you can't have negative time
means that it takes 8.97 seconds to hit the ground
