To determine the degree of an expression, you need to identify the term with the highest exponent. In this problem, there are only two terms. Let us analyze these terms:
12a^2b^2 – 5ab^5
First term: 12a^2b^2 = 2 + 2 = 4 (sum of their exponents)
Second term: 5ab^5 = 1 + 6 = 7 (sum of their exponents)
Therefore, the degree of this expression is 7.