A firecracker shoots up from a hill 140 feet high, with an initial speed of 100 feet per second. Using the formula H(t) = -16t2 + vt + s, approximately how long will it take the firecracker to hit the ground?

Five seconds

Seven seconds

Nine seconds

11 seconds

Question

A firecracker shoots up from a hill 140 feet high, with an initial speed of 100 feet per second. Using the formula H(t) = -16t2 + vt + s, approximately how long will it take the firecracker to hit the ground? 

 Five seconds

 Seven seconds 

Nine seconds 

11 seconds

anonymous · Answer

what am i solving for?

anonymous · Answer

X intercept @Cookiemonster32

anonymous · Answer

Are you allowed to use graphing calculators?

thomas5267 · Answer

Find v and s.  It is given in the question.

ttp · Answer

yes I am @swagmaster47 and the x intercept @Cookiemonster32