21.Watch the video and then solve the problem given below.

Click here to watch the video.

The table shows projections of sales(in billions ofdollars) of hepatitis C treatments for a certain region from 2012 to 2016. Complete parts(a) through(c).

Year

Sales($ billions)

2012

4.5

4.5

2013

4.8

4.8

2014

6.3

6.3

2015

8.1

8.1

2016

9.8

9.8

a. What is the quadratic function that best models these sales as a function of the number of years after2010? Let x represent the number of years after 2010 and y represent the number of billions of dollars in sales of treatments.