Me i usually know how to do this but i idk what i am doing wrong

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

Which graph represents the following piecewise defined function?