http://www.ck12.org Chapter 7. Organizing and Displaying Data - Basic
Solution:
The slope of the line ischange in xchange in y.
The slope of this line is^21. They−intercept is (0, 5). To graph this line, begin by plotting they−intercept. From the
y−intercept, move to the right one and up two. Plot this point. You can continue to move right one and up two in
order to create more points on the line. Join the points with a smooth line by using a straight edge (ruler).
If you found this difficult to do, you could make a table of values for the function by substituting values forxinto the
equation to determine values fory. Then you would plot the ordered pairs on the graph. Whichever way you plotted
the points, the result would be a straight line graph. Let’s apply this method to an everyday problem.
Example 3:Your school is having a teenage dance on Friday night. The dance will begin at 8:00 p.m. and will end
at midnight. A DJ is hired to play the music. The cost of hiring the DJ is $100 plus an additional $20.00 an hour.
Using either a table of values or an equation, draw a graph that would represent the cost of hiring the DJ for the
dance. How much would the school pay the DJ for playing music for the dance?
Solution:An equation that would model this problem isy= 20 x+100. To make the equation match the problem
ycan be replaced withc (cost)andxcan be replaced withh (number of hours). Now the equationy= 20 x+ 100
becomesc= 20 h+100.