And so because this is a constant and this is a constant, we can plug those values into this equation and we get 1.8 times ten to negative 16 is equal to this multiplied by this, our two unknowns divided by a constant. So 55.5. And so if we bring this to the left side, we multiply them out, we get 1.0 times ten to negative 14 is equal to the product of the concentration of the hydrogen ion and the concentration of that hydroxide ion. And this is always true at room temperature. So basically what this equation is, and let's call this equation A. And by the way, this is equation B, and this is equation A from equation B.