Determine the least common denominator LCD. The LCM of the denominators of fraction or rational expressions is also called least common denominator or LCD. Add And Subtract Rational Expressions Lesson Rational Expressions Algebra Lesson Plans Simplifying Expressions Xa xb Complex fraction without variables. Adding rational expressions with different denominators x+a x+b . By using this website you agree to our Cookie Policy. Write both addends with a common denominator. If the denominator is not equal to the LCD multiply the numerator and. If possible simplify by finding common factors in the numerator and denominator. To Add or Subtract Two Rational Expressions with Unlike Denominators 1. Bring down the columns. Combine the numerators and keep the LCD as the denominator. Add the numerators and keep the denominator the same. Rewrite each rational expression as an equivalent expression whose denominator is the LCD. X Adding and Subtracting Rational Express...