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Presented below is the production data for six months showing the mixed costs incurred by a manufacturer. Month Cost Units July $5,890 4,100 August 4,500 3,200 September 7.480 6,300 October 8.750 7,500 November 5,800 5,800 December 7,336 6,600 a) Using the high-low method, determine the cost function. b) If in January they expect to produce 7,500 units, what will the cost be