Which is NOT a polynomial?

Question 2 options:

4x4+3x3− 2x2−1

x5 − 5x4 + 4x3 −3x2

3x2 + 5x4 + 2x − 12

x3− 7x2 + 9x −20

Respuesta :

Polynomials need to fit these requirements:
-Can't have negetive exponents
-Can't be divided by a variable.