Prentice Hall Algebra 1

8-7 Factoring Special Cases

Objective

To factor perfect-square trinomials and the differences of two squares

Solve it: Anya says, “This problem is about the difference of squares.”
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Essential Understanding You can factor some trinomials by “reversing” the rules for multiplying special case binomials that you learned in Lesson 8-4.

For example, recall the rules for finding squares of binomials.

open eh plus b close squared . equals open eh plus b close open eh plus b close equals , eh squared , plus 2 eh b plus , b squared

open eh minus b close squared . equals open eh minus b close open eh minus b close equals , eh squared , minus 2 eh b plus , b squared

Any trinomial of the form eh squared , plus 2 eh b plus , b squared  or eh squared , minus 2 eh b plus , b squared  is a perfect-square trinomial because it is the result of squaring a binomial. Reading the equations above from right to left gives you rules for factoring perfect-square trinomials.

Here is how to recognize a perfect-square trinomial:

  • The first and the last terms are perfect squares.
  • The middle term is twice the product of one factor from the first term and one factor from the last term.

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Table of Contents

Prentice Hall Algebra 1 Chapter 1 Foundations for Algebra Chapter 2 Solving Equations Chapter 3 Solving Inequalities Chapter 4 An Introduction to Functions Chapter 5 Linear Functions Chapter 6 Systems of Equations and Inequalities Chapter 7 Exponents and Exponential Functions Chapter 8 Polynomials and Factoring Chapter 9 Quadratic Functions and Equations Chapter 10 Radical Expressions and Equations Chapter 11 Rational Expressions and Functions Chapter 12 Data Analysis and Probability Skills Handbook Reference Visual Glossary Selected Answers Index Acknowledgments