Answer:
A. 20x² + y and B. 20x² are polynomials.
Explanation:
Let's review each of the expressions given to define which are polynomials:
A. 20x² + y
It's a polynomial because all of the variables have integer exponents that are positive .
B. 20x²
It's a polynomial because the variable of this monomial have integer exponent that is positive .
C. 20x² + y ^1/2
It's not a polynomial because a term has a fraction exponent (y ^1/2).
D. 20x²/y
It's not a polynomial because a term has a negative exponent (y ^-1) and there is a variable in the denominator of a fraction.