Help with this please

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

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?  

These tables represent a quadratic function with a vertex at (0, -1). what is the average rate of change for the interval from x = 9 to x = 10?