Which is true about the degree of the sum and difference of the polynomials 3x5y – 2x3y4 – 7xy3 and –8x5y + 2x3y4 + xy3?

First we have to find the sum and the difference of those polynomials- The sum is: ( 3 x^5y - 2 x^3y^4 - 7 xy^3 ) + ( - 8 x^5y + 2 x^3y^4 + xy^3 ) = 3 x^5 - 2 x^3y^4 - 7xy^3 - 8 x^5y + 2 x^3y^4 + xy^3 = - 5 x^5y - 6 xy^3. And the difference: ( 3 x^5y - 2 x^3y^4 - 7 xy^3 ) - ( - 8 x^5y + 2 x^3y^4 + xy^3 ) = 3 x^5y - 2 x^3y^4 - 7 xy^3 + 8 xy^5 - 2 x^3y^4 - xy^3 = 11 xy^5 - 4 x^3y^4 - 8xy^3. The highest exponent in both polynomials is 5. The degree of the polynomials is 5.