Question 129592
Here goes the examples. 


Let P(x) be a third degree polynomial as per the data given by you. 


So P(x) = {{{x^3 + x^2 - x + 1}}} 


and Q(x) be a fourth degree polynomial.



Q(x) = {{{3x^4 - 2x^3 + 9x^2 - 8x + 15}}} 



So the addition of these would result in  the following



Adding like terms we get:


P(x) + Q(x) = {{{ 3x^4 - x^3 + 10x^2 - 9x + 16}}} 



thus the degree of the resulting polynomial would be equal to 4


Thus the solution



Regards