Using the given data you can build the linear regression (described by linear function y=ax+b) by hand or you can use math calculator to do this. In attached diagram you can see that

and

Then the equation of linear function is

Answer: correct choice is D.
It is already rounded to the tens because there is no digit but 0 in the ones digit. I hope this helped.
C I petty sure the answer is c
Ending balance:$10,613.15
Total interest paid:$1,615.96
Total payments:$3,462.81
Answer is b . G)f(x))=9x^3+30x