Can someone help me with part 2

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

Can someone me with this problem i don't understand i need

The constitution gives congress the power to create federal courts lower than the supreme court higher than the supreme court equal to the supreme court, unaffected by the supreme court.