9514 1404 393
Explanation:
The closure property for any operation and set says that performing the operation on members of the set will result in a member of the set.
The closure property for addition of polynomials says that the addition of any polynomials will result in a polynomial.
Examples:
1) 1 and x are polynomials, as is their sum: 1+x.
2) x^3 -5 and x+5 are polynomials, as is their sum: (x^3 -5) +(x+5) = x^3 -x.
