Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
7. Graphing Rational Functions
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Exercise 24 Page 711

Practice makes perfect
a We are told that the musicians will play a charity benefit and two of them will perform without charge. We have totally $ 1200 to pay them. Now we will write an equation to describe the cost c of hiring one paid musician as a function of the number of musicians m.
c=1200/m-2 Notice that we take the number of musicians as (m-2) because 2 of them will not be paid. Now we want to graph this function. To do so let's recall the general form of a rational function.

y=a/x- h+ k We need to have the asymptotes of the function to graph it. In this form, the asymptotes are the lines x= h and y= k. Let's now identify the values of h and k for our function. c =1200/m-2 &⇔ c=1200/m- 2+ 0 We can see that h= 2 and k= 0. Therefore, the asymptotes are the lines x= 2 and y= 0. With this in mind, we will make a table of values to plot the graph easily.

m 1200/m-2 c=1200/m-2
14 1200/14-2 100
26 1200/26-2 50
102 1200/102-2 12

Let's now plot and connect the obtained points with a smooth curve. Since the cost and the number of musicians cannot be negative, we will use only Quadrant I to draw the graph.

graph of the function
b We are asked to find the cost of hiring each paid musician when we use our entire budget to get a total of 18 musicians. To do so we will substitute 18 for m into the equation c= 1200m-2. Let's do it!
c=1200/m-2
c=1200/18-2
c=1200/16
c=75

We found that when 18 musicians play the benefit we need to pay $ 75 for the cost of hiring each paid musician.