Find the required linear model using least-squares regression.
The accompanying table shows the approximate amount (in billions of dollars) of student loans in repayment in various
quarters of 2015 and 2016. Let x = 1 correspond to the first quarter of 2015.
Quarter
Loans in Repayment
1, 500
2, 540
3, 560
4, 580
5, 610
6, 635
7, 660