3. Why can the numerator and denominator of a rational expression be divided by their common factors? What conditions must be placed on the value of the variables when a rational expression is simplified?

Step-by-step explanation:

Hello, do you agree that for any real number a (different from 0)

?

5/5 = 1 for instance.

So, when you have the same common factor at the numerator and at the denominator you can eliminate it. For instance.

You just need to be careful with 0, as dividing by 0 is not allowed.

Hope this helps

Thank you.