I need help btw i am in middle school

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

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)

Solve for n? [tex]z = \frac{3}{4} mn[/tex]