HELP ME PLZzZzZ
(im doing a quiz)

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

F(x) = (x^2 + 3x − 4) and g (x) = (x+4) find f/g and state the domain.

How do businesses a country's economy? a. by investing in goods and services b. by increasing the unemployment rate c. by making profits