The linear equation

y=0.15x+0.79

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 represent the year 20018?

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?

1 answer

A.Yr = 1997 + (x-1)
Yr = 1997 + (4-1) = 2000.

B. X = (2018-1997) + 1 = 22.

C. Y = 0.15x + 0.79.
m = 0.15.

D. Y-int. = 0.79.

E.The cost of gas before 1997.

F. C = 0.15*22 + 0.79 = $4.09.