Help me with the last part at the bottom please it says x = I don't know what to put so please help and thanks

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

Miguel’s teacher asks him to color 4/8 of his grid. he must use 3 colors: red, blue, and green. there must be more green sections than red sections. how can miguel color all the sections of his grid to follow all the rules

Acircle has a circumference of 28.36 units what is the diameter of the circle