The temperature at which a liquid and solid state of a substance are in equilibrium is the same as the melting point when going from solid to liquid and the freezing point when going from liquid to solid.

Here's why:

* Equilibrium: When a substance is at its melting/freezing point, the rate at which solid molecules are turning into liquid molecules is equal to the rate at which liquid molecules are turning into solid molecules. This dynamic balance is what we call equilibrium.

* Melting Point: The melting point is the temperature at which a solid changes into a liquid.

* Freezing Point: The freezing point is the temperature at which a liquid changes into a solid.

It's important to note that:

* The terms "melting point" and "freezing point" refer to the same temperature.

* This temperature can vary slightly depending on pressure, but for practical purposes, we can consider them the same.

Let me know if you have any other questions!