In the algebraic term 5xy, the coefficient is the number which is 5
Then the coefficient is the number included in the term
The given expression is

We can simplify it first by adding the like terms as 3 and 5

We have 3 terms, 2 algebraic and 1 numeric
7b, -18a are algebraic
8 is numeric
The coefficients of the algebraic terms are 7 and -18
The numeric term has no coefficient
Then the answers are
7 and -18