SOLUTION: Ray threw a ball from the top of a 40 metre building to his sister who was standing below him on a balcony that is 12 m up from the ground. The function h(t)=-2t^2-10t+40 models th

Question 1034472: Ray threw a ball from the top of a 40 metre building to his sister who was standing below him on a balcony that is 12 m up from the ground. The function h(t)=-2t^2-10t+40 models the height of the ball from the ground, where h(t) is the height in metres and t is the time in seconds. If Ray's throw is accurate, when will his sister catch the ball?
Show your solution using the factoring method.
Thanks so much :)
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The ball has to drop 28 meters and h(t) must be 12 feet.
h(t)=12=-2t^2-10t+40
-2t^2-10t+28=0
divide everything by minus 2
t^2+5t-14=0
(t+7)(t-2)=0
positive root only. t=2 seconds.At that point, h(t)=12.

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