I'm confused I put 13-x and it said incorrect?? HELP!

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 other information do you need to prove triangle dac=bca by asa

What is the location of point g, which partitions the directed line segment from d to f into a 5: 4 ratio? –1 0 2 3