What is y=-x + 4, x+y=4

For how answer my question this will be the last question can you answer in math subject

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

Prove that 16^4-2^13-4^5 is divisible by 11.