Apple iPhone sales (in millions of units) between 2007 and 2015 can be closely modeled by the polynomial function = () = 0.4442 3 + 7.0873 2 0.2478 + 3.9307, where is time in years since 2007. Graph this function in an appropriate window, label completely. What is the -intercept, and what does this tell you in practical terms? What sales does this model predict in the year 2013? (Note that the actual sales were 153.5 million that year.) Do you think this model can be used to predict sales into the future, such as in the year 2022? Why or why not?