Expert: Steve Holleran - 5/24/2008

Question
4.   The line

y=0.15x + 0.79

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

0.11x-y=-0.85

estimates the price of gasoline in January of each year (Bureau of Labor Statistics, 2006).
  Do you expect the lines to be intersecting, parallel, or perpendicular?

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

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


Answer
Hi Kizzy,


Okay, the first line is y = 0.15x + 0.79 and the second is

                       y = 0.11x + 0.85

Since they don't have the same slope (first one has m = 0.15, second one has m = 0.11), they will intersect.

I would expect that makes sense, since you want your estimate to equal the cost at some point.

Don't know if you needed it, but the intersection point is (1.5, 1.015)

Steve