Example

Adding 3x3+2x2\frac{3}{x-3} + \frac{2}{x-2}

Add two rational expressions whose denominators are distinct linear binomials:

3x3+2x2\frac{3}{x - 3} + \frac{2}{x - 2}

Step 1 — Find the LCD and rewrite each fraction. The denominators (x3)(x - 3) and (x2)(x - 2) are already fully factored and share no common factor, so the LCD is their product: (x3)(x2)(x - 3)(x - 2). The first fraction is missing the factor (x2)(x - 2); the second is missing (x3)(x - 3). Multiply each by the appropriate form of 11:

3(x2)(x3)(x2)+2(x3)(x3)(x2)\frac{3(x - 2)}{(x - 3)(x - 2)} + \frac{2(x - 3)}{(x - 3)(x - 2)}

Step 2 — Add the numerators over the common denominator. Distribute in each numerator and combine:

3x6+2x6(x3)(x2)=5x12(x3)(x2)\frac{3x - 6 + 2x - 6}{(x - 3)(x - 2)} = \frac{5x - 12}{(x - 3)(x - 2)}

Step 3 — Simplify, if possible. The binomial 5x125x - 12 cannot be factored further and shares no common factor with the denominator, so the result is already in simplified form:

5x12(x3)(x2)\frac{5x - 12}{(x - 3)(x - 2)}

This example demonstrates the complete three-step procedure for adding rational expressions with different polynomial denominators. When two linear binomial denominators share no common factor, the LCD is simply their product. After rewriting, the numerators are expanded, combined, and then checked for common factors with the denominator.

Image 0

0

1

Updated 2026-04-30

Contributors are:

Who are from:

Tags

OpenStax

Elementary Algebra @ OpenStax

Ch.8 Rational Expressions and Equations - Elementary Algebra @ OpenStax

Algebra

Math

Prealgebra

Intermediate Algebra @ OpenStax

Ch.7 Rational Expressions and Functions - Intermediate Algebra @ OpenStax

Related
Learn After