NEED HELP! just with the 1st 2

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

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

The area of a circle is equal to 1 dm². find the radius of the circle.