Can anyone answer these three inverse variation questions? (3) I'll give you best answer!?

1. Find an equation of variation where y varies directly as x, and y=10 when x=8 2. Find an equation of variation where y varies inversely with x, and y=10 when x=3 3. Suppose x varies jointly as w and y and inveresely as z, and x=4 when w= 12, y=10, and z=5. Find x when w=9, y=14, and z=0.1