SOLUTION: Topics In Contemporary Math Linear Growth 3) The amount spent (in billions of dollars) for ads online is shown. Year 2010 2011 2012 2013 2014 2015 Amount $68.4 $80.2 $

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Question 1192978: Topics In Contemporary Math
Linear Growth

3) The amount spent (in billions of dollars) for ads online is shown.
Year 2010 2011 2012 2013 2014 2015
Amount $68.4 $80.2 $94.2 $106.1 $119.8 $132.1

a) Use the 2010 and 2015 values to find the average change in the amount spent per
year.

b) Write an explicit formula for the amount spend on ads online, if we consider 2010
as year 0.

c) How much would this model predict was spent on online advertisements in 2020?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The difference between those two years is 132.1-68.4=63.7 units billions of dollars.
divide by 5 to get a slope or the average per year over the interval of 12.74
the formula uses point slope where y-y1=m(x-x1) m slope and (x1, y1) point
y-68.4=12.74x
y=12.74x+68.4
in 2020, x=10
y=127.4+68.4=$195.8 billion.