At the end of our equilibrium, this guy is x. And since this and this is a ratio of one to one, this guy must be x two. So the concentration of this guy increases by x. The concentration of this guy increases by x, and the concentration of this guy decreases by x because this guy dissociates into this guy. So we get our hydronium concentration, we represent as x. Our pyruvate concentration we present as x because we begin with this concentration divide by since we begin with this amount of Peruvic acid and then some dissociates into the conjugate base, we say that it's 0.5 minus x.