Help, what do I do with those numbers?

On a trip, you had to change your money from dollars to british pounds.  you got  560  pounds for  800  dollars.  which is a unit rate that describes the exchange

Apublic library wants to place 4 magazines and 9 books on each display shelf. the expressions 4s +9s represents the total number of items that will be displayed on s shelves. simplify this expression

Which number completes the system of linear inequalities represented by the graph? y> 2x – 2 and x + 4y 2 et 2 3 4