So we can write our rate laws in the following manner. The rate of the first step is equal to k one. Our constant going this way times the concentration of this guy to the first power because we have a coefficient of one times the concentration of BR also to the first power because we have a coefficient of 1 mol. Now this equals to the reverse reaction because we're assuming our equilibrium or the first reaction reached equilibrium. And so this rate equals this rate, the reverse rate. So this guy equals the constant minus one going this way times the concentration of this guy.