Solve for x: y = 2x + 3
y - 3 = 2x
(y - 3)/2 = 2x/2
(y - 3)/2 = x
Switch around and you get:
x = (y - 3)/2
...even though it's still the same.
Heh heh...
Solve for q:
r = (s - 1)/(1 + q)
r(1 + q) = (s - 1)/(1 + q)*(1 + q)
r + rq = s - 1
rq = s - r - 1
q = (s - r - 1)/r
Well, let's see if I can convert my answer back to r to check...
q = (s - r - 1)/r
r(q) = (s - r - 1)/r*r
rq = s - r - 1
r + rq = s - 1
r(1 + q) = s - 1
r(1 + q)/(1 + q) = (s - 1)/(1 + q)
r = (s - 1)/(1 + q)
Okay, that's enough. I'm done! 
