Will give medal!
Which of the following shows that polynomials are closed under addition when two polynomials 4x2 − 8x − 7 and −5x + 16 are added?

Question

Will give medal! 
Which of the following shows that polynomials are closed under addition when two polynomials 4x2 − 8x − 7 and −5x + 16 are added?

anonymous · Answer

4x2 − 13x + 9 may or may not be a polynomial
 4x2 + 13x − 23 may or may not be a polynomial
 4x2 − 13x + 9 will be a polynomial
 4x2 + 13x − 23 will be a polynomial

anonymous · Answer

c option just add them
sum of 2 polynomial is always polynomial

anonymous · Answer

1 think its C but 1'm not sure...

anonymous · Answer

$$4x^2 − 8x − 7 +(−5x + 16)=4x^2-13x+9$$
As a result you got another polynomial => "4x2 − 13x + 9 will be a polynomial"