The answer is v= -8x/-xy+9
Here is the step by step process (This is going to be long):
1. 9v+8x=vxy
Multiply both sides by vx
2. 9v+8x+−vxy=vxy+−vxy
−vxy+9v+8x=0
Add -vxy to both sides
3. −vxy+9v+8x+−8x=0+−8x
−vxy+9v=−8x
Add -8x to both sides
4. v(−xy+9)=−8x
Factor out the variable v
5. v(-xy+9)/-xy+9 = -8x/-xy+9
v = -8x/-xy+9
Divide both sides by -xy+9