! Required information [The following information applies to the questions displayed below.) Phillips Company manufactures air-conditioning units for commercial buildings and has noticed considerable variation in shipping expenses from month to month as per the data below: Month January February March April May June July Units Shipped 4 4 5 2 3 6 8 Total Shipping Expense $ 1,680 $ 2, 580 $ 1,950 $ 1,212 $ 1,800 $ 2, 220 $ 3,072 4. What is the cost formula for shipping expenses? Y =