1. The degree of 2ab + 5a + 3 is 2 because the highest exponent is in the 2ab term.
2. The degree of x + y + z is 1 because all terms have degree 1.
3. The degree of 15x + 14y^2z^4 is 8 because the y^2z^4 term has degree 8.
4. The degree of 2y + 31 is 1 because 2y has degree 1.
5. The degree of -9x is 1 because x has degree 1.
6. The degree of 4 is 0 because it is a numerical term.
7. The degree of -2b^3 + 7b^2 + 13 is 3 because -2b^3 has the highest degree of 3.
8. The degree of -8a^4 + 5a is 4 because -8a^4 has degree 4.
9. The degree of 3bc^2 + 2b - 7 is 3 because 3bc^2 has degree 3.
10. The degree of 10 is 0 because it is a numerical term.