By definition we have to:
A set has under an operation if performance of that operation on set members always produces a member of the same set; in this case we also say that the set is closed under the operation.
For this case we have the following polynomials:

Multiplying we have:

The product of two polynomials is also a polynomial.
Answer:
d
is a polynomial
Answer:
look below bestie
Step-by-step explanation:
ok so i dont know most of it (sryy) but the area of the entire pizza is 535.84in², the radius of the pizza is about 13.05 and yea. thats all i got
Answer:
D
Step-by-step explanation:
For it to be a function, every x value must have 1 unique y value ONLY.
In option A, you can see that the x value of 1 has 2 y values, 1 & 5. So it's not a function.
In option B, you can see that the x value of 0 has 2 y values, 0 & -4. Moreover, the x value of 4 also has 2 y values, 2 & -2. So it's not a function.
In option C, you can see that the x value of -2 has 2 y values, 4 & -4. This is not a function as well.
In option D, each x value has a unique y value that are different. So this is a function.
Answer is option D.