144. Mobile First Company The following table shows Facebook's monthly active users in millions who use a mobile only platform. Year 2012 2013 2014 2015 Users (millions) 100 260 450 725 Source: Business Insider. a. Discuss the general trend in users during this time period. b. Would a linear function model this data well? Explain. c. What other type of function might work? d. If a parabola is used to model this data, will it open upward or downward? Explain. e. Find a quadratic function U that models the data. f. Estimate the number of mobile users in 2016. Did your estimate use interpolation or extrapolation