Help please I will give brainliest​

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

What is the base of 1/9 to the power of 2

Hiroaki wants to find 3 3/4 - 7/8 explain why he must rename 3 3/4 to do the subtraction.