This guy is equal to notice inside this log we're multiplying ka times this whole thing, this ratio. So another way of expressing this is to use the logs of logs and we get log of ka plus log of this guy. So the concentration of the conjugate axis divided by the concentration of conjugate base. Now our next step is to basically rewrite this guy in the form of the PH formula. We can't say this guy is equal to PH because remember, PH is negative log of this guy. So let's take the negative of the whole expression.