Can some give me the equations or tips on how to find them myself? (if you can't read it, or can't see the picture, message me)

Divide the following fractions 3/4 ÷ 2/3 1/2 8/9 9/8 2

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

If you double the input of a function and it results in half the output, and if you triple the input and it results in a third of the output, what can be guessed about the function? check all that apply.