In 1990, the cost of tuition at a large Midwestern university was $101 per credit hour. In 1999, tuition had risen to $227 per credit hour.

Question

Determine a linear function �(�) to represent the cost of tuition as a function of �, the number of years since 1990.		�(�)=
In the year 2007, tuition will be $  per credit hour.
In the year , tuition will be $367 per credit hour

Answer 1

1990 $101

1999 $227

as an equation of a line, it's a line through points (0,101) and (9, 227)

which has slope = (227-101)/9 = 126/9 = 14

y-101 = 14x

14x-y = -101

y= 14x +101

year 2007 = 1990 + 17, x=17

y = 14(17)+101 = $339 per credit in 2007

367 = 14x +101

14x = 367-101= 266

x = 266/14 = 133/7 = 19= 1990+19= the year 2009