Chapter 7 Section 4 Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley

Adding and Subtracting Rational Expressions Add rational expressions having the same denominator. Add rational expressions having different denominators. Subtract rational expressions

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1 Objective 1 Add rational expressions having the same denominator. Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Add rational expressions having the same denominator. We find the sum of two rational expressions with the same procedure that we used in Section 1.1 for adding two fractions having the same denominator. Slide If and (Q ≠ 0) are rational expressions, then That is, to add rational expressions with the same denominator, add the numerators and keep the same denominator.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 1 Add. Write each answer in lowest terms. Solution: Adding Rational Expressions with the Same Denominator Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2 Objective 2 Add rational expressions having different denominators. Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley We use the following steps, which are the same as those used in Section 1.1 to add fractions having different denominators. Add rational expressions having different denominators. Slide Step 1: Find the least common denominator (LCD). Step 2: Rewrite each rational expression as an equivalent rational expression with the LCD as the denominator. Step 3: Add the numerators to get the numerator of the sum. The LCD is the denominator of the sum. Step 4: Write in lowest terms using the fundamental property.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Add. Write each answer in lowest terms. EXAMPLE 2 Solution: Adding Rational Expressions with Different Denominators Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 3 Solution: Adding Rational Expressions Slide Add. Write the answer in lowest terms.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 4 Solution: Adding Rational Expressions Add. Write the answer in lowest terms. Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 5 Add. Write the answer in lowest terms. Solution: Adding Rational Expressions with Denominators That Are Opposites Slide

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 3 Objective 3 Slide Subtract rational expressions.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley We subtract rational expressions having different denominators using a procedure similar to the one used to add rational expressions having different denominators. Subtract rational expressions. Slide If and (Q ≠ 0) are rational expressions, then That is, to subtract rational expressions with the same denominator, subtract the numerators and keep the same denominator. Use the following rule to subtract rational expressions having the same denominator.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Subtract. Write the answer in lowest terms. EXAMPLE 6 Subtracting Rational Expressions with the Same Denominator Slide Solution: Sign errors often occur in subtraction problems. The numerator of the fraction being subtracted must be treated as a single quantity. Be sure to use parentheses after the subtraction sign.

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 7 Subtracting Rational Expressions with Different Denominators Slide Subtract. Write the answer in lowest terms. Solution:

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE 8 Subtracting Rational Expressions with Denominators That Are Opposite Slide Subtract. Write the answer in lowest terms. Solution:

Copyright © 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Subtract. Write the answer in lowest terms. EXAMPLE 9 Subtracting Rational Expressions Slide Solution: