Lesson 3

In Discover, two different ways to determine the lowest common multiple (LCM) for any group of denominators were explored. Retrieve your results and review the two methods—the factored form method and the product and GCF method.

Once you have a full understanding of finding the lowest common denominators (LCD) with rational expressions, complete Try This 5. Remember, the same method can be applied to the addition and subtraction of rational expressions with different denominators. As usual with rational expressions, non-permissible values must be considered.

Try This 5

1. Simplify the following rational expression using the steps you discussed in Try This 4.
   
   
    
   
2. Verify your results.

Save your responses in your course folder.

Share 4

With a partner, discuss any differences in your responses to Try This 5. Make any necessary revisions once a consensus has been reached. This will give both of you a better understanding of the process required.

1. Describe a procedure that can be followed to determine the sum or difference, in simplest form, of rational expressions with different monomial denominators.
2. Refer to the graphing method of verifying your answers.
   1. What do you have to watch out for when using this method?
   2. Describe a different method you could use to verify your answers.
3. After verification, did you or your partner need to revise your calculations? Were you able to find your error(s)?

If required, save a record of your discussion in your course folder.