# equations

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I am not great at equations... I keep practicing and working these problems and questions out but I always seem to get different answers can someone please guide me on how or tell me the correct way to work these problems out>>

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?

My answer is = year 2000

b)What x-value represents the year 2018?

x= 22

c)What is the slope (or rate of change) of this equation?

How or where do I start on this one??

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

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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?

My answer is = year 2000
2000 is correct. You might make the next part easier by looking at how this was done, instead of just counting up 4.
1996 + 4 = 2000.

b)What x-value represents the year 2018?
1996 + 18 = ??
x= 22

c)What is the slope (or rate of change) of this equation?
The equation for a straight line is
y = mx + b where m is the slope. The equation given is
y=0.15x + 0.79; therefore, 0.15 is the slope.

How or where do I start on this one??

d)What is the y-intercept?
The y intercept is the 0.79 in the original equation. It is the point at which the line crosses the y axis (and x = 0 at that point).
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
Use the equation, plug in x for the number of years (check me out but I think that will be 22) and solve for y.

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thank you dr. bob