I think it’s positive. As it gets heavier, the cost has a positive slope, or increases. I’m not absolutely sure though 
 
        
                    
             
        
        
        
1 minute = 60 seconds
300 seconds / 60 seconds = 5 minutes
        
                    
             
        
        
        
The correct answer is: [C]:  " c(x) = –8x²<span> + 3x – 5 " .
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  The quadratic function takes the form of:
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  " f(x) =  ax</span>²  + bx + c " .
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Answer choice:  [C]:  " c(x) = –8x² + 3x – 5 "  ;
  is the only answer choice provided that takes that form of the quadratic function:
  " f(x) =  ax²  + bx + c " :
in which:  " a = -8 " ; " b = 3 " ;  " c = -5 " .
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Answer:
x = the number
Step-by-step explanation:
15.) 2x + 9 = 25
16.) 3x - 6 = 21
17.) 7x = 12 + 3x
18.) 4x = 18 + x
19.) 2x + 24 = 8x
20.) 30 - x = 4x