PLZZZ HELP
Tell why these expressions are not polynomials

Answer:
Step-by-step explanation:
In polynomials, variables will not have negative sign.
So,
[tex]26) 3n^{-2} + 2n + 23 \\\\28) 5x^{4}+\frac{1}{3x^{3}}\\\\29) \frac{5}{x^{n}}[/tex]are not polynomials