=+Estimated monthly purchases for this part based on expected demand of the two products for the rest of the year are:

Month Purchase quantity expected October 2800 parts November 3100 December 2500 Required 1 The computer in Pat’s office is down and Pat has been asked to provide immediately an equation to estimate the future purchase cost for part no. 4599. Pat grabs a calculator and uses the high–low method to estimate a cost equation. What equation does Pat get?