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| Question 73425:  I am having problems with this one.This is what I have so far.
 x=number of items produced
 C=cost in dollars
 100items=$10,000
 300items=$22,000
 Business and finance. In planning for a new item, a manufacturer assumes that
 the number of items produced x and the cost in dollars C of producing these items are related by a linear equation. Projections are that 100 items will cost $10,000 to produce and that 300 items will cost $22,000 to produce. Find the equation that relates C and x.
 
 Answer by bucky(2189)
      (Show Source): 
You can put this solution on YOUR website! Since this is a linear equation by assumption, the slope-intercept form can be used.  This equation will be in the form y = mx + b.  But we will redefine the variables.  Replace
 y with C the cost. x will still be used to represent the number of items produced. x will be on
 the x-axis and C will be on the y-axis.
 .
 As the number of items manufactured increases from 100 to 300 units (an increase of 200 items)
 the cost goes from $10,000 to $22,000 (an increase of $12,000).  The slope of this graph is,
 therefore:
 .
 
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 and the 60 represents the dollars that it costs to produce a unit.
 .
 So far our equation is:
 .
 
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 The question now is how do we calculate b? We can use the fact that when x = 100, then
 C = $10,000. Plug these values into the equation and you find:
 .
 
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 This simplifies to:
 .
 
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 Subtract 6000 from both sides and you find that
 .
 
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 Plug that value into the equation and you get:
 .
 
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 This is the equation that relates C and x (thenCost and number of items produced).
 Notice something interesting.  If you produced no items (x = 0) the cost is still $4000.
 This probably involves the cost of labor to maintain the assembly line, store the materials,
 keep the lights and heat on, and so forth.
 .
 Hope this helps you to understand the graphing process.  You can check the equation out
 by letting x = 300 items and see if the cost computes to $22,000 as specified in the problem.
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