What is a function in math?

if you explain I will make you brainiest!

At a book fair, joe bought 24 books at 3 for $5 and had $2 left. how much money did he have at first?

Francis is getting new carpet tiles in his living room and den. his living room and den are connected. he needs to figure out how much carpet he needs and the cost involved. if each tile costs $2.00 per sq ft, how much would it cost to have new tile put in the den? a) $24 b) $36 c) $48 d) $54 plz awnser soon

Find four solutions of the given function. write the solutions as ordered pairs. 4x – y = 4