Question

The line y=0.15x +0.79
represents an estimate of the average cost of gasoline each year.
The line 0.11x-y+-0.85
estimates the price of gasoline in January of each year (“Consumer price index,” 2006).
a. Do you expect the lines to be intersecting, parallel, or perpendicular? Explain your reasoning.

b. 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 1

the second equation could be re-written as:
y=0.11x+-0.85
the slope of the first equation (number in a front of x) = 0.15, but second =0.11
which is means that lines are not parallel or perpendicular...

Answer 2

parallel lines should have the same slope & perpendicular ones :
m1=-1/m
so, lines are intersecting.

Answer 3

so if they aren't perpendicular or parallel are they intersecting?

Answer 4

intersecting (no other choice :) )

Answer 5

Just making sure. also I am a little confused between questions a and b it seems they are asking the same question?

Answer 6

pretty much the same. just enforcing that you understand that parallel lines have the same slope (coefficient in a front of x)

Answer 7

ok so just to make sure before I answer this question...I would answer the questions as follows.

a. I suspect that the lines are intersecting, because the numbers are not the same

b. They are not parallel because the slopes are not matching numbers

c. Part B did confirm part a.