SOLUTION: 2. A toy rocket is fired into the air from the top of a barn. Its height (h) above the ground in yards after t seconds is given by the function h(t)=−5t2+10t+20. Show clear solut

Question 1172180: 2. A toy rocket is fired into the air from the top of a barn. Its height (h) above the ground in yards after t seconds is given by the function h(t)=−5t2+10t+20. Show clear solutions thanksss!
a. What was the maximum height of the rocket?
b. How long was the rocket in the air before hitting the ground?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
h(t)=-5t^2+10t+20
maximum height is where t=-b/2a or -10/-10 or 1 second after leaving.
that is 25 feet high.
-
set the equation equal to 0
-5(t^2-2t-4)=0
t=(1/2)(2+/- sqrt 20); sqrt (20) is 2 sqrt(5), the numerator 2s cancel
=1+/-sqrt(5)
3.236 seconds, only positive root

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