Question

3. The linear equation



represents an estimate of the average cost of gas for year x starting in 1997 (“Consumer price index,” 2006). The year 1997 would be represented by x = 1, for example, because 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

Answer 1

a. is 2000

Answer 2

how did you get that without an equation?
I would just say these questions cannot be answered since there was not enough information given.

Answer 3

im sorry the equation is y=0.5x+0.79

Answer 4

so for the first one you plug in x=4 correct?

Answer 5

after that im lost

Answer 6

oh since x=4, then the year is 2000 ok gj
now for b....

Answer 7

so x=1 we have 1997
x=2 we have 1998
x=3 we have 1999
x=4 we have 2000 and so on..
so the equation for the year would be Z=1996+x
lets see for x=1, we get Z=1996+1=1997
for x=2 we get Z=1996+2=1998
and so on...
so the question is what is x if Z=2018
so we have 2018=1996+x solve this equation for x

Answer 8

what did you get when you solved the equation that i just typed for x?

Answer 9

x=22

Answer 10

ok cool so did you understand everything for b?

Answer 11

no not really by u breaking it down help me find the answer

Answer 12

I just made up a variable for the year

Answer 13

can we do the next one c

Answer 14

k it wants to know the slope of the line? what is the slope of any line in this form y=mx+b?

Answer 15

m=

Answer 16

is that correct

Answer 17

yes

Answer 18

so y=.5x+79 has slope_________?

Answer 19

what is m?

Answer 20

ok 1 min

Answer 21

slope=m=.5

Answer 22

ok

Answer 23

oh ok the slope is .5
and would b=79

Answer 24

or the answer to the ? is just .5

Answer 25

the question c is just looking for slope so it would be .5
the question d is just looking for the y intercept so it would be .79 (I forgot the decimal when I typed it a sec ago)

Answer 26

therefore the y-intersect would b =0

Answer 27

the y-intercept is when x=0

Answer 28

than im lost on problem e

Answer 29

ok we will come back to it then lets look at the last one average gas is y=.5x+.79
and since we are looking at yr 2018 then x=22
so the average gas for yr 2018 is y=.5(22)+.79

Answer 30

y=11.79

Answer 31

ok back to e.
the y-intercept is when x=0 because if we were to graph a point on the y axis x would always be zero since we aren't going left and right any from the origin.
for example graph (0,5) and (0,-6). where are these points?

Answer 32

would it be -11