The following information is available for a company's cost of sales over the last five months:

Month	Units Sold	Cost of Sales
June	0,900	52,500
July	0,800	50,000
August	1,200	60,000
September	1,600	70,000
October	1,800	75,000

Using the high-low method for managing expenses, the company's cost equation is: _____________________.

Note: This is the only question that requires an answer that is not just numerical. For uniformity of answers do not include the currency sign.

SOLUTIONS IN EXCEL FORMAT PLS