text: Fixed cost becomes the intercept of your equation.\nSlope is given by the cost per item.\nYou can calculate the cost per item, as (4610-220)/5 (=total cost - fixed cost, the result divided by number of items).\nThis gives a slope of 4390/5=878\n\nso, c(x)= 220 + 878x\nx stands for items, result for c(x) is in dollars\n\n(notice that you are assumingo you can produce items one by one and not at packs of five; otherwise you wouldn't have a straight line because to produce one or to produce five would have the same cost)\n----\nIn the second case, base rate 2.00 is the intercept and cents per minute is the slope; x stands for minutes, result for c(x) is in dollars:\nc(x) = 2.00 + 0.20x\nTry and figure how a cab CO charge works...