Respuesta :

The 5th degrees could cancel out to be a polynomial of degree 4. Similarly for lower degrees. 
But it can't be a 6th degree.
konrad509
No.

Example
[tex]P(x)=x^5+x+3\\ R(x)=-x^5+3x-4\\\\ P(x)+R(x)=x^5+x+3+(-x^5)+3x-4=4x-1 [/tex]