View more at http://www.MathTutorDVD.com. In this lesson, you will learn how to work with rational expressions in algebra. We will learn to simplify these types of expressions by fully multiplying the numerator and denominators together, then simplifying the result. Rational functions consist of the numerator begin a polynomial and the denominator also being a polynomial, so the normal rules of multiplication and division of fractions also apply to rational expressions. The only difference is that the resulting rational expression must be simplified by canceling terms in order to get the final answer.