posted by Nellie .
A model rocket Is launched from a height of 50ft. The formula h=-16t^2+70t +50 describes the rocket's height,h,in feet seconds after it was launched. How long will it take the rocket to reach to reachthe ground?
When it's at the ground h = 0
-16t^2+70t+50 = 0
using the quadratic formula
t cannot be negative, so t=5s is the correct answer.