1. The linear equation

represents an estimate of the average cost of gas for year x starting in 1997. The year 1997 would be represented by x = 1, for example, as it is the first year in the study. Similarly, 2005 would be year 9, or x = 9.

a) What year would be represented by x = 4?

b) What x-value represents the year 2018?

c) What is the slope (or rate of change) of this equation?

d) What is the y-intercept?

e) What does the y-intercept represent?

f) Assuming this growth trend continues, what will the price of gasoline be in the year 2018? How did you arrive at your answer?

2. The line

represents an estimate of the average cost of gasoline for each year. The line

estimates the price of gasoline in January of each year (Bureau of Labor Statistics, 2006).

g) Do you expect the lines to be intersecting, parallel, or perpendicular? Explain your reasoning.

h) Use the equations of the lines to determine if they are parallel. What did you find?

i) Did your answer to part b confirm your expectation in part a?