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The height of a ball when it is thrown off a cliff can be represented by the equation $h=45-7t-6t^2$, where $t$ is time in seconds. In how many seconds will the ball reach a height of 25 feet?

 Dec 9, 2020
 #1
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We need to solve this

 

-6t^2  - 7t  +  45  =  25

 

-6t^2    -7t  +  20   =   0

 

(-2t - 5)  ( 3t - 4)  = 0

 

Only the econd factor produces a  positive  result  for t

 

3t  - 4   =   0

 

3t   = 4

 

t =  4/3    seconds

 

 

 

cool cool cool

 Dec 9, 2020

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