How do you use order of operation to evaluate experessions

What is the slope of the line that contains the points (4,8) and (9,8)? what type of line is it?

Answer question above and explain each step : )

Mr and mrs smith buy tickets for themselves and their four children. the cost of an adult ticket is ? 6 more than the adult ticket. the total cost of the six tickets is ? 40.50 work out the cost of an adult ticket. in your working let c be the cost of the child ticket and a be the cost of the adult ticket.