A local Best buy store reported that it sold 561 iphone 6 pluses on the day that they became available. Five days later, the sales were down to 196 iphone 6 pluses. Assume that the relationship between number of days since the phone became available and number sold is linear and let x= the number of days since the phone became available and y= number of phones sold at this Best Buy store.

a) Write two ordered pairs to represent the sales on the days described.

b) Find the slope of the line through those ordered pairs

c) Write an equation in point-slope form of the line.

d) Convert the equation to slope-intercept form.

e) Explain in one or two sentences what the slope means in the context of this problem.