# What is the constant in this algebraic expression 5a+2?

The constant is $2$. See explanation.
A constant is a term in expression which contains only a number (positive, or negative) without any variables (letters). Here an expression is a sum of 2 smaller expressions. The term $5 a$ contains a variable $a$, so it is not a constant.
The term $2$ does not contain any letters, so it is a constant.