Joe Natal is a farmer who produces and packages applesauce. Apples can be stored for several months in cold storage, so applesauce production is relatively uniform throughout the year. The recently hired controller for the firm is about to apply the high-low method in estimating the company's energy cost behavior. The following costs were incurred during the past 12 months: (3 + 3 = 6 points)

Month	Pints of applesauce produced	Energy cost
January	105,000	$70,200
February	63,000	66,300
March	66,000	66,000
April	72,000	67,350
May	90,000	68,700
June	96,000	70,050
July	120,000	84,000
August	90,000	68,400
September	90,000	69,000
October	84,000	68,100
November	123,000	72,300
December	117,000	74,850

a) Use the high-low method to estimate the company's energy cost behavior and express it in equation form.

b) Predict the energy cost for a month in which 78,000 pints of applesauce are produced.