Answer:
Step-by-step explanation:
The two given polynomials written by Cory and Melissa are:
and 
Now, adding both the given polynomials, we get

=
Thus, the degree of the sum of the two polynomials is 7.
Now, subtracting both the given polynomials, we get

=
Thus, the degree of the difference of two polynomials is 5.
Therefore, there is a difference between the degree of the sum and the degree of the difference of the polynomials.