So, in this case summation of xi that means summation of PT into y by Piv that should be equal to 1. Now in this case when this you know that at which temperature you can get this equality is equal to 1 after substitution of Antonio's equation.
সুতরাং এক্ষেত্রে xi এর সামেশন অর্থাৎ PT ইন্টু yi বাই Piv এর সামেশন হবে ইকুয়াল টু 1 ।