Chapter 3.3, Problem 16E

High School Graduates The following table shows the number, in millions, graduating from high school in the United States in the given year.

Year	Number graduating (in millions)
$1985$	$2.83$
$1987$	$2.65$
$1989$	$2.47$
$1991$	$2.29$

a. By calculating difference, show that these data can be modeled using a linear function.

b. What is the slope for the linear function modeling high school graduations? Explain in practical terms the meaning of the slope.

c. Find a formula for a linear function that models these data.

d. Express, using functional notation, the number graduating from high school in 1994, and then use your formula from part c to calculate that value.