Question

Which among the following is not a polynomial?

• A. $7x^3-z^3+4y^3$
• B. $7x^3-z^{\frac{1}{3}}+\frac{4}{y^3}$
• C. $7-z^3+4y^6$
• D. $7x^3-z^9+5y^3$

Answer 1

The correct option is B $7x^3-z^{\frac{1}{3}}+\frac{4}{y^3}$

$\underset{–}{Concept}$:
Degree of each variable in a polynomial is a whole number.

$\underset{–}{Method}$:
$7x^3-z^{\frac{1}{3}}+\frac{4}{y^3}$
Exponents of $z$ and $y$ in this expression is not a whole number.
This fails to become a polynomial.

In contrast, if we look at other options, all variables have exponents as a whole number.