Intermediate Algebra (11th edition)

260 CHAPTER 4 Systems of Linear Equations

If the rates of growth between 1990 and 2000

continue, the populations of Houston, Phoenix,

Dallas, and Philadelphia will follow the trends

indicated in the graph. Use the graph to work

Exercises 1 and 2.

1. (a)Which of these cities will experience
   population growth?
   (b)Which city will experience population
   decline?
   (c)Rank the city populations from least to
   greatest for the year 2000.


2. (a)In which year will the population of
   Dallas equal that of Philadelphia? About
   what will this population be?
   (b)Write as an ordered pair (year, popu-
   lation in millions) the point at which Houston and Phoenix will have the same
   population.

3.Use a graph to solve the system.

Solve each system by substitution or elimination. If a system is inconsistent or has dependent

equations, say so.

x+y= 7

x-y= 5

TEST

CHAPTER 4

View the complete solutions to
all Chapter Test exercises on
the Video Resources on DVD.

Step-by-step test solutions are found on the Chapter Test Prep Videos

available via the Video Resources on DVD, in , or on

(search “LialIntermediateAlg”).

CHAPTER

VIDEOS

1990 2000 2010 2020 2030

1.0

1.5

2.0

2.5

3.0

3.5 PROJECTED

Population (in millions)

The Growth Game

Size of cities if the rate of population

growth from 1990 to 2000 continues:

Source: U.S. Census Bureau,

Chronicle research.

PhoenixDallas

Houston

Philadelphia

Year

4.

y=-

2

3

x

2 x- 3 y= 24 5.

2 x+ 6 y= 3

3 x- y=- 8 6.

3 x=

5

4

y+ 2

12 x- 5 y= 8

7.

2 x-y= 3

3 x+y= 12 8.

6 x+ 3 y=- 6

• 5 x+ 2 y=- 4 9.
  8 y= 7 - 6 x

3 x+ 4 y= 8

10.

3 x+ 10 y- 2 z= 6

6 x+ 5 y+ z= 0

3 x+ 5 y+ 3 z= 2 11.

y+ 2 z= 0

x-y- z= 4

4 x+y+ z= 11

Solve each problem using a system of equations.

12.Harrison Ford is a box-office star. As of January 2010, his two

top-grossing domestic films, Star Wars Episode IV: A New

Hopeand Indiana Jones and the Kingdom of the Crystal

Skull,earned $778.0 million together. If Indiana Jones and

the Kingdom of the Crystal Skullgrossed $144.0 million less

than Star Wars Episode IV: A New Hope,how much did each

film gross? (Source:www.the-numbers.com)

13.Two cars start from points 420 mi apart and travel toward

each other. They meet after 3.5 hr. Find the average rate

of each car if one travels 30 mph slower than the other. 420 mi