Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
5. Using Linear Models
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Exercise 19 Page 98

Practice makes perfect
a

Let x and y represent Per Capita Revenue and Per Capita Expenditure, respectively.

State Per Capita Revenue ($) Per Capita Expenditure ($)
Arizona 4144 3789
Georgia 3904 3834
Maryland 5109 4557
Mississippi 5292 4871
New Mexico 6205 5793
Nevada 4345 3723
New York 7081 6891
Texas 4030 3442
Utah 5439 4459

Let's plot the points on the coordinate plane.

A trend line is a line that approximates the relationship between the variables or data sets of a scatter plot. Remember that the trend line may vary for each person based where they decided to draw their line of fit. Let's sketch it!

To write the equation of the line, we should first determine its slope. Therefore, we will choose two points on the line. Looking at the graph, we can choose the points (4000,3516) and (6400,5940). Let's use the Slope Formula!

m = y_2-y_1/x_2-x_1
m = 5940- 3516/6400- 4000
m=2424/2400
m=1.01

Now that we know the slope of the line and a point that it passes through, we can write the equation in the point-slope form. Let (6400,5940) be our reference point. y-y_1=m(x-x_1) ⇕ [0.5em] y-5940=1.01(x-6400) By isolating y, we can rewrite the equation in slope-intercept form to make it a bit easier to understand.

y-5940=1.01(x-6400)
y-5940=1.01x-6464
y=1.01x-524

b

By substituting 3000 for x into the equation of the trend line, we can find the expenditure of the state. Let's do it!

y=1.01x-524
y=1.01( 3000)-524
y=3030-524
y=2506

The state would spend about $2506 per capita.

c

We have been told that Ohio spent $5142 per capita during the year. Let's substitute 5142 for y into the equation and solve it for x to find Ohio's revenue.

y=1.01x-524
5142=1.01x-524
5666=1.01x
5609.900990...=x
x=5609.900990...
x≈ 5610

Therefore, its revenue is about $5610.

d

To decide whether the revenue and expenditure of New Jersey follows the trend, we will substitute 5825 for x into the equation and solve it for y.

y = 1.01x-524
y=1.01( 5825)-524
y=5883.25-524
y=5359.25

Since the value that we found is close to $5348, the information follows the trend.