Solids and Liquids in K expression

[Jaira_Murphy_2D]

When writing the K expression and there's a solid or liquid in the reaction, should I balance the whole equation first and then not include the solid or liquid in my K expression? Or ignore the solid or liquid from the beginning and balance my the equation without them?

[Ethan Baurle 1A]

Balance your equation first and then omit the ones that are solids are liquids.

[Tony Chung 2I]

Balance the entire equation first, and then omit the liquids and solids. This will reduce the chance of you making an error.