Howling Wolf is right...Basic rule with equations is whatever you do...always
do it to both sides
@sportscout: apparently that's what they call it now. when I was at school, it was solve for k...For some reason "they" think they have to change terminology every decade (or so).
@Bugmeiser: Close.. but you might want to rethink that procedur
Edit, since you postet again: I refer to this
multiply both sides by root b then turn the whole thing upside down