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| Question 633223:  Aki's bicycle designs has determined that when x hundred bicycles are built, the average cost per bicycle is given by c(x)=0.2x²-1.3x+8.181, where c(x) is in hundreds of dollars.
 The shop should build_____bicycles.
 Answer by KMST(5328)
      (Show Source): 
You can put this solution on YOUR website!  is a quadratic function. As a quadratic function with a positive coefficient for the term in
  , it goes through a minimum.
 Quadratic functions have the general form
 
  They graph as parabolas,
 and have a minimum or maximum at
  . In the case of
  , there is a minimum at
  -->  -->  So the cost per bicycle is minimum when
  hundred bicycles are built. That is
  
 ABOUT QUADRATIC FUNCTIONS:
 For a quadratic function,
  , when the leading coefficient,
  , is positive, the function grows without bounds as
  increases on both ends (positive and negative), as the
  term overwhelms whatever value the rest of the polynomial could take. As a consequence the function looks like a smile, with a minimum in the middle:
 
  If
  the shape of the graph is flipped and the function has a maximum: 
  The maximum or minimum is the vertex of the parabola.
 The function can be transformed algebraically from
  to 
  which shows that the extreme value (maximum or minimum) occurs when
 
  , when  and the line represented by
  is the axis of symmetry of the parabola that is the graph of the function. If the expression reminds you of the quadratic formula, it is no coincidence.
 The quadratic formula comes from the same
 
  making  .
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