A 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	Units Shipped	Total Shipping Expense
January	4		$	2,160
February	4		$	3,060
March	5		$	2,550
April	2		$	1,284
May	3		$	2,160
June	6		$	2,940
July	8		$	4,224

4. What is the cost formula for shipping expenses?

Y= ______ + _______X