Agrocery store wants to examine the relationship between the sales amounts each day at two different locations, store a and store b. the sales amount each day in dollars was recorded for 10 days at each store. the least square regression line is y= -3000+1.2x where x represents the sales amounts each day at the store q and y represents the sales amount each day at store b. if the mean of the 10 sales amounts for store b is $45000 what is the mean of the 10 sales amounts for store a?