Final answer:
The constant in the expression 6a+2b+5 is the number 5, which is a fixed value unlike the variable terms 6a and 2b.
Step-by-step explanation:
The constant in the expression 6a+2b+5 refers to the term that does not change regardless of the values of the variables involved. In an algebraic expression, variables, often represented by letters like a and b, can take various values, while a constant is a specific fixed number. In this case, the number 5 is the only term without a variable attached, making it the constant.