Tell me question no 3

Dear student,

A polynomial expression consist of the operations that is subtraction or addition of the terms that has a constant and one or more than one variables and the variable bares a positive integer.

Thus,
i) is a polynomial expression with one variable of the fourth degree due to highest exponent being 4.
ii) is not a polynomial expression since the variable with the positive exponent is present in the denominator which makes its exponent to be negative as,
$\frac{1}{x^2}=x^{-2}$
​​​​iii) is a polynomial expression with two variables of the fourth degree due to highest exponent being 4.
​​​​iv) is a polynomial expression with two variables of the third degree due to highest exponent being 3.

Regards