# Math 116

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could someone please evaluate what i have so far and help me with the last few questions...

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. similarily, 2005 would be year 9, or x=9.
a) what year would be represented by x = 4? 2000
b) what x-value represents the year 2018? 22
c) what is the slope (or rate of change) of thsi equation?
2018: 0.15(22) + 0.79 = \$4.09
1997: \$0.94

4.09–0.94 divided by 2018-1997
= 3.15 divided by 21
= 0.15
= answer is \$0.15 per year

d) what is the y-intercept? no idea
e) what does the y-intercept represent? where the line crosses on the graph
f) assuming this growth trend continues, what will the price of gas be in 2018? how did you arrive at thsi answer?
2018: 0.15(22) + 0.79 = \$4.09
1997: 0.15(1) + 0.79 = \$0.94

4.09–0.94 divided by 2018-1997
= 3.15 divided by 21
= 0.15 = \$0.15 per year

• Math 116 -

a, b and c are correct.
d) The y-intersept (where x = 0) is y = 0.79
e) The x-intercept (where y = 0) is
x = -0.79/0.15 = -5.267
f) \$4.09 is correct. Your other calculations are unnecessary