Eventually, the concentration of this guy and this guy at equilibrium will be exactly constant. They won't be the same, although they could be the same, but they will be constant. The concentration of x will not change and the concentration of Y will also not change. And that means our rate of the reverse reaction this way and the rate of the four reaction known this way will be the same. Now, once again, it's important to understand that the concentration of x and Y in equilibrium will not be the same. They could be the same, but it's not necessary for them to be the same.