Chapter 11 - Rational Expressions and Functions - 11-4 Adding and Subtracting Rational Expressions - Lesson Check - Page 687: 7

A. yes B. no

A. Yes, she is correct because the product of the denominators will always have the LCD as the factor. B. No, look at this example $(x+1)/4+(x-1)/12$ In the example above, 48 is a common denominator but is not the least common denominator.