The total public debt D (in trillions of dollars) in the United States at the beginning of each year from 2008 through 2014 can be approximated by the model D 0 071t2 2 94t 10 0, 8 curren t curren 14 where t represents the year, with t 8 corresponding to 2008 (Source U S Department of the Treasury)...

a t 8 9 10 11 12 13 14 D 898 1071 1230 1375 1506 1622 1724 Sometime during the year 2010 the total p ...

The total public debt D (in trillions of dollars) in the United States at the beginning of

Question:

The total public debt D (in trillions of dollars) in the United States at the beginning of each year from 2008 through 2014 can be approximated by the model
D = ˆ’ 0.071t2 + 2.94t ˆ’ 10.0, 8 ‰¤ t ‰¤ 14
where t represents the year, with t = 8 corresponding to 2008. (Source: U.S. Department of the Treasury)
(a) Use the model to complete the table to determine when the total public debt reached $13 trillion.

(b) Verify your result from part (a) algebraically and graphically.
(c) Use the model to predict the total public debt in 2025. Is this prediction reasonable? Explain.