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Introductory and Intermediate Algebra for College Students

We used two data points and an exponential function to model the population of the United States from 1970 through 2009. The data are shown again in the table. Use all five data points.

$$\begin{array}{c|c}

\hline x, \text { Number of Years after } 1969 & y, \text { U.S. Population (millions) } \\

\hline 1(1970) & 203.3 \\

\hline 11(1980) & 226.5 \\

\hline 21(1990) & 248.7 \\

\hline 31(2000) & 281.4 \\

\hline 40(2009) & 307.0 \\

\hline

\end{array}$$

Use the values of $r$ in Exercises $45-48$ to select the two models of best fit. Use each of these models to predict by which year the U.S. population will reach 352 million. How do these answers compare to the year we found in Example $1,$ namely $2020 ?$ If you obtained different years, how do you account for this difference?