SOLUTION: Benjamin threw a rock straight up from a cliff that was 24ft above the water. If the height of the rock​ h, in​ feet, after t seconds is given by the equation h equals negati

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Question 1133275: Benjamin threw a rock straight up from a cliff that was
24ft above the water. If the height of the rock​ h, in​ feet, after t seconds is given by the equation h equals negative 16 t squared plus 20 t plus 2 h=−16t2+20t+24​, how long will it take for the rock to hit the​ water?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The equation's "24" is the height above the water. Solve this for h=0, water level
-16t^2+20t+24=0
-4t^2+5t+6=0 or 4t^2-5t-6=0
(4t+3)(t-2)=0
t=2 only positive root.
2 seconds ANSWER
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