Agroup of 19 students want to see the show at the planetarium. the tickets cost $11 for each student who is a member of the planetariums frequent visitor program and $13 for each student who is not a member. the total cost of the students' tickets is $209.

let x represent the number of students in the group who are members of the frequent visitor program. write an expression in terms of x for the number of students in the group who are not members. then write an equation to determine the value of x.