Answer 
4 and 5
Explanation
A constant term in an expression is a term that does is independent of any variables. This means that constant term will have non of the variables 
 attached to them. In the expression
 attached to them. In the expression 
 we notice that the terms integers 4 and 5 are the only terms that are not coefficients of any of the variables in the expression.
 we notice that the terms integers 4 and 5 are the only terms that are not coefficients of any of the variables in the expression.