# RATL 2 | Lesson 1 | Solutions (Rational Expressions)

1. radical in the numerator which means the variable does not have an integer exponent
2. division by a variable and therefore, the variable could be zero
3. division by zero
4. exponent that is a variable
1. Your list should include the examples from number 1: radicals, division by zero, variables as exponents, and division by a variable.

Note: If the numerator and/or denominator are not polynomials by definition, then the expression cannot be a rational expression.