You can put this solution on YOUR website! Find y:
p/m=b/m^2(y/a+z)
------------
I found it, it's just to the right of the (
===========
Ok, let's get serious.
Find y:
p/m=b/m^2(y/a+z)
-----------
p=b/m(y/a+z)
pm = by/(a+z)
pm(a+z) = by
y = pm(a+z)/b