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This section covers the fundamentals of rational expressions, which are fractional expressions consisting of polynomials in their numerator and denominator. It explains domains, simplification techniques, and operations such as addition, subtraction, multiplication, and division of rational expressions. Key concepts like identifying restrictions, factoring completely, and utilizing the least common denominator (LCD) are emphasized. Additionally, it presents examples to illustrate each operation and the process of rationalizing numerators and denominators.
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Chapter 1 - Fundamentals Section 1.4 Rational Expressions 1.4 - Rational Expressions
Definitions • Fractional Expression A quotient of two algebraic expressions is called a fractional expression. • Rational Expression A rational expression is a fractional expression where both the numerator and denominator are polynomials. 1.4 - Rational Expressions
Domain The domain of an algebraic expression is the set of real numbers that the variable is permitted to have. 1.4 - Rational Expressions
Basic Expressions & Their Domains 1.4 - Rational Expressions
Simplifying Rational Expressions To simplify rational expressions we must • Factor the numerator and denominator completely. • State the restrictions or domain. • Reduce the common factors from the numerator and denominator. 1.4 - Rational Expressions
Example 1 • Simplify the following expression. 1.4 - Rational Expressions
Multiplying Rational Expressions To multiply rational expressions we must • Factor the numerator and denominator completely. • State the restrictions or domain. • Multiple factors. • Reduce the common factors from the numerator and denominator. 1.4 - Rational Expressions
Example 2 • Perform the multiplication and simplify. 1.4 - Rational Expressions
Dividing Rational Expressions To divide rational expressions we must • Factor the numerator and denominator completely. • State the restrictions or domain. • Invert the divisor and multiply. • State new restrictions. • Reduce the common factors from the numerator and denominator. 1.4 - Rational Expressions
Example 3 – pg. 42 #33 • Perform the multiplication and simplify 1.4 - Rational Expressions
Adding or Subtracting Rational Expressions To add or subtract rational expressions we must • Factor the numerator and denominator completely. • State the restrictions or domain. • Find the LCD. • Combine fractions using the LCD. • Use the distributive property in the numerator and combine like terms. • If possible, factor the numerator and reduce common terms. 1.4 - Rational Expressions
Example 4 – pg. 42 #48 Perform the addition or subtraction and simplify. 1.4 - Rational Expressions
Compound Fractions • A compound fraction is a fraction in which the numerator, denominator, or both, are themselves fractional expressions. 1.4 - Rational Expressions
Simplifying Compound Fractions To simplify compound expressions we must • Factor the numerator and denominator completely. • State the restrictions or domain. • Find the LCD. • Multiply the numerator and denominator by the LCD to obtain a fraction. • Simplify. • If possible, factor. 1.4 - Rational Expressions
Example 5 – pg. 42 #60 Perform the addition or subtraction and simplify. 1.4 - Rational Expressions
Rationalizing • If a fraction has a numerator (or denominator) in the form then we may rationalize the numerator (or denominator) by multiplyting both the numerator and denominator by the conjugate radical . 1.4 - Rational Expressions
Example 6 – pg. 43 #81 • Rationalize the denominator. 1.4 - Rational Expressions
Example 7 – pg. 43 #87 • Rationalize the numerator. 1.4 - Rational Expressions