Simple Algerbraic Manipulation is Confusing Me

[mrlucky0]

I'm working on a chemistry problem and I'm trying to follow the derivation for % ionization (of a weak acid or base) but I can't seem to understand how rearrangement of eq. 6 results in eq. 7.

In more general terms, I started with the Hendreson Hasselbalch equation:

pH = pka + log(A-/AH)

What I want to find is, A-/(AH + A-)

This is giving me a real headache, can anyone help?

 

[neutrino]

Bring the A^- to the LHS of (6). Add 1 to both sides and convert the LHS to a single fraction. Invert the fractions and multiply by 100.

 

[mrlucky0]

Thanks, I've got it now.