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Jordan tosses a coin off a bridge into the riverThe height of the cain, f(x) , feet, is represented by the function f(x) = - 16x ^ 2 - 16x + 60 where x represents the time.  In seconds, how long is the coin in the air?

 Mar 3, 2021
 #1
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We only need to find the positive root......this will give us the  time

 

-16x^2  - 16x  + 60  =    0         

 

16x^2  + 16x  - 60  =  0       divide  through by  4

 

4x^2 + 4x - 15  =  0      factor

 

(2x - 3) ( 2x + 5)  =   0

 

Set  the  first factor =  0  and solve  for  x

 

2x - 3  =  0

 

2x =  3

 

x =  3/2 sec   = 1.5  sec

 

 

cool cool cool

 Mar 3, 2021

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