SOLUTION: SLOPE QUESTION PLEASE HELP! Find the slope of the line that goes through the points: (4,-9),(4,6) Application Question: Super cost. The average cost of a 30-second

Algebra ->  Linear-equations -> SOLUTION: SLOPE QUESTION PLEASE HELP! Find the slope of the line that goes through the points: (4,-9),(4,6) Application Question: Super cost. The average cost of a 30-second      Log On


   



Question 969552: SLOPE QUESTION PLEASE HELP!

Find the slope of the line that goes through the points:
(4,-9),(4,6)
Application Question:
Super cost. The average cost of a 30-second ad during the 1998 Super Bowl was $1.3 million, and in 2009 it was $3million (www.adage.com). Use the slope of 0.1554 to predict the average cost in 2014.
Please explain the steps as to how you got to the answer, that way I can understand you better. :) Thank youin advance!

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
a) given (4,-9),(4,6) find slope
slope = (y2 - y1) / (x2 - x1)
slope = (6 - (-9)) / (4 - 4) = 15 / 0
slope is undefined since division by 0 is not defined
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b) take 1998 as year 0 and x be (chosen year - 1998), then y (cost) is
y = 0.1554x + 1.3
let's test the equation for year 2009 since we know the cost for that year is $3 million
y = (0.1554 * 11) + 1.3 = 3.0094 approx $3 million and our equation checks, therefore
for 2014, (2014 - 1998) = 16 and
y = (0.1554 * 16) + 1.3 = 3.7864
average cost is $3.7864 million