And so we replace the concentration A with concentration B and we replace k one with K minus one. And remember that if this reaction achieves equilibrium, then the rate of the forward will be equal to the rate of the reverse and these two quantities will be equal. Now notice, k one is not necessarily equal to K minus one. K one is only equal to K minus one if the concentration of A is equal to the concentration of b when equilibrium is actually achieved. So normally k one is not the same as k minus one. Now, what exactly is the meaning of k?