The number of visits to U.S. libraries was 1.59 billion in 2009, and it increased by about 0.05 billion visits per year until 2014 (Source: Institute of Museum and Library Services). Let v be the number of visits (in billions) to U.S. libraries in the year that is t years since 2009.
a. Find an equation of a linear model to describe the situation.
b. Solve the equation you found in part (a) for t.
c. Use the equation you found in part (a) to estimate in which year there were 1.8 billion visits.
d. Use the equation you found in part (b) to estimate in which year there were 1.8 billion visits.
e. Compare your results from parts (c) and (d). Which equation was easier to use? Explain.
f. Which equation is easier to use to estimate the number of U.S. library visits in 2011? Explain. Then find that number of visits.