Please help, high school math

Acarnival sold tickets for $1.50 for adults and $1.00 for students. there were 54 tickets sold for a total of $70.50. write a system of equations to represent the number of adult tickets, x, and the number of student tickets, y. find the solution and explain what it means. i'll you if you me

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Which value would be a solution for x in the inequality 47-4x< 7