Definition of Rational Expression

This problem is a lot simpler if we factor all the expressions involved before proceeding:

Next let's remember how we divide one fraction by another—by multiplying by the reciprocal:

In this form, we can see that a lot of terms are going to start canceling with each other. All that we're left with is just .

The rational expression is a ratio of two polynomials.

The denominator cannot be zero.

An example of a rational expression is:

The answer is:

Because the denominator cannot be zero, the domain is all other numbers except for 1, or

We know that is equivalent to or .

By this property, there is no way to get from .

Therefore the correct answer is .