in the vapor summation of the you know vapor phase composition will be equal to 1 and also summation of the liquid phase composition will be equal to 1. Now, at equilibrium conditions you know that yi will be equal to Ki xi.
ಈಗ, ಸಮತೋಲನ ಪರಿಸ್ಥಿತಿಗಳಲ್ಲಿ, yi = Ki xi .