What is the arithmetic sequence equation

Brent wants to know what is 5 x 1/2

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?  

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180