Lesson 1

Rational Expressions

Recall the definition of a rational number: a real number that can be expressed in the form , where a and b are integers and b ≠ 0.

 

A rational expression has a similar definition. A rational expression can be expressed in the form of , where a and b are polynomials and b ≠ 0.

 

Retrieve your work from Try This 1. In that activity you picked a number and applied a series of mathematical operations to the number. You should have obtained the following rational expression to describe the result:

 

 

You may have noticed that the result is always two less than the original number. For example, if you started with the number 19, your final result was 17. You may have also determined that there was one number that does not follow this pattern.

 

Share 1

 

Confirm that x = −2 does not yield the same result as any other value of x. You may want to use a calculator to do this. What does your calculator show when a rational expression is undefined?

 

With a classmate discuss why x = −2 does not follow the same pattern.

 

Save your responses in your course folder.