Answer:

Explanation:
The general expression of a polynomial of degree n in the variable x is expressed mathematically as:


Considering the previous definition, let's analyze every expression:

It is not polynomial, because the variable is in the denominator.

It is a polynomial, because the exponents of the variables are positive integers.

It is not polynomial, because in the expression there is an exponent that is not a positive integer

It is not polynomial, because the variable is in the denominator.