Answer:
In this expression 18 is constant
Step-by-step explanation:
In this expression
6a + a + 3b + 18
18 is constant
According to definition of constant in algebra
In Algebra, a constant is a number on its own,
Example: in "x + 5 = 9", 5 and 9 are constants.
So
From the def of constant it is clear that in this expression 6a + a + 3b + 18
18 is constant