A cost analyst collected the following information for the Machining Department: Observation Machine-hours Total Operating Costs July 8,000 $60,000 August 9,200 66,000 September 7,600 61,000 October 8,800 64,000 November 9,000 65,000 Required: a. Determine the cost formula with machine-hours as the cost driver using the high-low method. b. If December's estimated machine-hours total 8,400, what is the estimated cost of the Machining Department