INTERMEDIATE ALGEBRA FOURTH EDITION Alan S. Tussy ■ R. David Gustafson Citrus College Rock Valley College Christo © 1991 Volz Wolfgang Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Intermediate Algebra, Fourth Edition © 2009, 2005Brooks/Cole, Cengage Learning Alan S. Tussy, R. David Gustafson ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be Executive Editor: reproduced, transmitted, stored, or used in any form or by any means, graphic, electronic, or Charlie Van Wagner mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Development Editor: Web distribution, information networks, or information storage and retrieval systems, except as Danielle Derbenti permitted under Section 107or 108of the 1976United States Copyright Act, without the prior Assistant Editor: written permission of the publisher. Laura Localio For product information and technology assistance, contact us at Editorial Assistant: Cengage Learning Customer & Sales Support, 1-800-354-9706 Lynh Pham Technology Project Manager: For permission to use material from this text or product, submit all Ed Costin requests online at cengage.com/permissions Further permissions questions can be emailed to Senior Marketing Manager: [email protected] Greta Kleinert Marketing Assistant: Cassandra Cummings Library of Congress Control Number: 2007940739 ISBN-13: 978-0-495-38973-6 Marketing Communications Manager: ISBN-10: 0-495-38973-0 Darlene Amidon-Brent Project Manager, Editorial Production: Brooks Cole Cheryll Linthicum 10 Davis Drive Belmont, CA 94002-3098 Creative Director: USA Rob Hugel Senior Art Director: Cengage Learning is a leading provider of customized learning solutions with office locations Vernon T. Boes around the globe, including Singapore, the United Kingdom, Australia, Mexico, Brazil, and Japan. Locate your local office at international.cengage.com/region. Print Buyer: Judy Inouye Cengage Learning products are represented in Canada by Nelson Education, Ltd. Permissions Editor: For your course and learning solutions, visit academic.cengage.com. Bob Kauser Purchase any of our products at your local college store or at our preferred online store Production Service: www.ichapters.com. Graphic World Inc. Text Designer: Terri Wright Photo Researcher: Terri Wright Illustrator: Lori Heckelman Cover Designer: Terri Wright Cover Image: Wolfgang Volz ©1991 Christo Cover Printer: Transcontinental Printing / Interglobe Compositor: Graphic World Inc. Printed in Canada 1 2 3 4 5 6 7 12 11 10 09 08 In memory of my mother, Jeanene, and in honor of my dad, Bill. —AST In memory of my teacher and mentor, Professor John Finch. —RDG This page intentionally left blank CONTENTS 1 A REVIEW OF BASIC ALGEBRA 1 1.1 The Language of Algebra 2 1.2 The Real Numbers 10 1.3 Operations with Real Numbers 23 1.4 Simplifying Algebraic Expressions Using Properties of Real Numbers 37 1.5 Solving Linear Equations Using Properties of Equality 49 1.6 Solving Formulas; Geometry 63 1.7 Using Equations to Solve Problems 75 1.8 More about Problem Solving 86 Chapter Summary and Review 102 Chapter Test 113 Group Project 115 2 GRAPHS, EQUATIONS OF LINES, AND FUNCTIONS 117 2.1 The Rectangular Coordinate System 118 2.2 Graphing Linear Equations in Two Variables 132 2.3 Rate of Change and the Slope of a Line 146 2.4 Writing Equations of Lines 161 2.5 An Introduction to Functions 176 2.6 Graphs of Functions 192 Chapter Summary and Review 206 Chapter Test 216 Group Project 218 Cumulative Review 218 3 SYSTEMS OF EQUATIONS 221 3.1 Solving Systems of Equations by Graphing 222 3.2 Solving Systems of Equations Algebraically 235 3.3 Problem Solving Using Systems of Two Equations 246 3.4 Solving Systems of Equations in Three Variables 263 3.5 Problem Solving Using Systems of Three Equations 275 3.6 Solving Systems of Equations Using Matrices 282 3.7 Solving Systems of Equations Using Determinants 294 Chapter Summary and Review 305 Chapter Test 314 Group Project 315 Cumulative Review 316 v vi CONTENTS 4 INEQUALITIES 319 4.1 Solving Linear Inequalities in One Variable 320 4.2 Solving Compound Inequalities 335 4.3 Solving Absolute Value Equations and Inequalities 347 4.4 Linear Inequalities in Two Variables 360 4.5 Systems of Linear Inequalities 370 Chapter Summary and Review 380 Chapter Test 387 Group Project 389 Cumulative Review 390 5 EXPONENTS, POLYNOMIALS, AND POLYNOMIAL FUNCTIONS 393 5.1 Exponents 394 5.2 Scientific Notation 408 5.3 Polynomials and Polynomial Functions 417 5.4 Multiplying Polynomials 434 5.5 The Greatest Common Factor and Factoring by Grouping 447 5.6 Factoring Trinomials 459 5.7 The Difference of Two Squares; the Sum and Difference of Two Cubes 473 5.8 Summary of Factoring Techniques 483 5.9 Solving Equations by Factoring 488 Chapter Summary and Review 503 Chapter Test 512 Group Project 514 6 RATIONAL EXPRESSIONS AND EQUATIONS 515 6.1 Rational Functions and Simplifying Rational Expressions 516 6.2 Multiplying and Dividing Rational Expressions 530 6.3 Adding and Subtracting Rational Expressions 542 6.4 Simplifying Complex Fractions 554 6.5 Dividing Polynomials 565 6.6 Synthetic Division 576 6.7 Solving Rational Equations 584 6.8 Problem Solving Using Rational Equations 596 6.9 Proportion and Variation 606 Chapter Summary and Review 622 Chapter Test 634 Group Project 635 CONTENTS vii 7 RADICAL EXPRESSIONS AND EQUATIONS 641 7.1 Radical Expressions and Radical Functions 642 7.2 Rational Exponents 658 7.3 Simplifying and Combining Radical Expressions 671 7.4 Multiplying and Dividing Radical Expressions 683 7.5 Solving Radical Equations 696 7.6 Geometric Applications of Radicals 708 7.7 Complex Numbers 721 Chapter Summary and Review 734 Chapter Test 743 Group Project 745 8 QUADRATIC EQUATIONS, FUNCTIONS, AND INEQUALITIES 747 8.1 The Square Root Property and Completing the Square 748 8.2 The Quadratic Formula 761 8.3 The Discriminant and Equations That Can Be Written in Quadratic Form 773 8.4 Quadratic Functions and Their Graphs 783 8.5 Quadratic and Other Nonlinear Inequalities 799 Chapter Summary and Review 811 Chapter Test 818 Group Project 820 Cumulative Review 821 9 EXPONENTIAL AND LOGARITHMIC FUNCTIONS 825 9.1 Algebra and Composition of Functions 826 9.2 Inverse Functions 838 9.3 Exponential Functions 850 9.4 Base-eExponential Functions 866 9.5 Logarithmic Functions 875 9.6 Base-eLogarithmic Functions 889 9.7 Properties of Logarithms 897 9.8 Exponential and Logarithmic Equations 909 Chapter Summary and Review 922 Chapter Test 933 Group Project 934 viii CONTENTS 10 CONIC SECTIONS; MORE GRAPHING 937 10.1 The Circle and the Parabola 938 10.2 The Ellipse 952 10.3 The Hyperbola 962 10.4 Solving Nonlinear Systems of Equations 973 Chapter Summary and Review 981 Chapter Test 986 Group Project 988 11 MISCELLANEOUS TOPICS 989 11.1 The Binomial Theorem 990 11.2 Arithmetic Sequences and Series 1000 11.3 Geometric Sequences and Series 1011 Chapter Summary and Review 1024 Chapter Test 1028 Group Project 1029 Cumulative Review 1030 APPENDIXES APPENDIX 1: Roots and Powers A-1 APPENDIX 2: Answers to Selected Exercises A-3 INDEX I-1 PREFACE Intermediate Algebra, Fourth Edition, is more than a simple upgrade of the third edition. Substantial changes have been made to the example structure, the Study Sets, and the peda- gogy. Throughout the process, the objective has been to ease teaching challenges and meet students’educational needs. Algebra, for many of today’s developmental math students, is like a foreign language. They have difficulty translating the words, their meanings, and how they apply to problem solving. With these needs in mind (and as educational research suggests), the fundamental goal is to have students read, write, think, and speak using the language of algebra. Instruc- tional approaches that include vocabulary, practice, and well-defined pedagogy, along with an emphasis on reasoning, modeling, communication, and technology skills have been blended to address this need. The most common student question as they watch their instructors solve problems and as they read the textbook is . . . Why?The new fourth edition addresses this question in a unique way. Experience teaches us that it’s not enough to know how a problem is solved. Students gain a deeper understanding of algebraic concepts if they know whya particular approach is taken. This instructional truth was the motivation for adding aStrategyand Whyexplanation to the solution of each worked example. The fourth edition now provides, on a consistent basis, a concise answer to that all-important question: Why? This is just one of several changes in this revision, and we trust that all of them will make the course a better experience for both instructor and student. NEW TO THIS EDITION • New Example Structure • New Chapter Opening Applications • New Study Skills Workshops • New Chapter Objectives • New Guided Practiceand Try It Yourselfsections in the Study Sets • New End-of-Chapter Organization ix