Pls pls help me with this

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

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)

A. s.a.! this is a similarity in right triangles. next (solve for x)a.) 12b.) 5c.) 12.5d.) [tex] 6\sqrt{3} [/tex]