Posted by nicole on .
A model rocket is launched from a height of 50 feet. the formula: h=16t^2+70t+50 describes the rocket's height,h,in feet t seconds after it was launched. how long will it take the rocket to reach the ground.

Intermediate Algebra 
Reiny,
when it hits the ground, h = 0
16t^2 + 70t + 50 = 0
8t^2  35t  25 = 0
(t5)(8t + 5) = 0
t = 5 or t = 5/8, but t can't be negative
so it will hit the ground in 5 seconds.