9514 1404 393
Answer:
 

Explanation:
When y varies jointly as x and z, the equation is written ...
 y = k·x·z
Here, the joint variation is not with z, but with z². There is also an inverse variation with w, so the entire relation is ...
 y = k·x·z²/w
We want to find the value of k for the given values of the variables. So, we can solve for k to get ...
 

Then the equation of variation is ...
 
