Question of the day: solve this equation. can 1/5 be divided?

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

Simplify the expression. -2/5(10+15m-20n)

Two numbers have a sum of -19. one number is x. what expression represents the other number?