okay, let's do this~
we want v isolated on one side so let's bring w over through subtraction
now we have 5/9v=z-w
now, to get rid of that fraction attached to v, we will multiply it's reciprocal on both sides.
*the reciprocal of 5/9 is 9/5
(5/9) x (9/5) cancel each other leaving v isolated to the left
the other side should look like this 9/5(z-w)
now we put both parts together to end up with:
v= 9/5(z-w)
there you go! :D