They are equations, not functions.
I am asking people to show the steps to rearrange (and manipulate) the equations.
How do I get from w/v = g/(v-w)
to 1/v + 1/w = 1/g ?
How do I get from w-g = f²(1/(v-g))
to 1/v + 1/w = 1/g ?
The point Grandad was making is that you can't change from one to the other, they simply aren't equivalent. From w/v= g/(v-w), you can get that 1/g= v/(w(v-w)) but that is NOT equal to 1/v+ 1/w.
The second one has an "f" in it but the equation you want to change it into doesn't. Again, that is NOT possible.