## linear equations of gas prices

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
jonesbetty
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Joined: Mon Nov 07, 2011 10:00 pm
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### linear equations of gas prices

1) 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, 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 2010? How did you arrive at your answer

2) 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.
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?

maggiemagnet
Posts: 358
Joined: Mon Dec 08, 2008 12:32 am
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### Re: linear equations of gas prices

1) 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, 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
Use what they explained in the last two sentences of the exercise.
b) what x-value represents the year 2018
Use the same bit to answer this part, too.
c) what is the slope or rate of change of this equation
Look at the slope-intercept equation they gave you, and copy down the slope value.
d) what is the y-intercept
Look at the slope-intercept equation they gave you, and copy down the intercept value.
e)what does the y-intercept represent
Try this lesson, if you're not sure.
f) assuming this growth trend continues, what will the price of gasoline be in the year 2010? How did you arrive at your answer
Find the x-value for "2010" using the method you used for (a) and (b). Plug this in and simplify.
2) 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.
a) do you expect the lines to be intersecting, parallel, or perpendicular? explain your reasoning