II$-$ HOW TO PLOT THE EQUILIBRIUM STATE?

Consider the following dehydrogenation reaction:

a$-$ Drive the equilibrium constant equation function of $P_t$ and $x_e$

b$-$ Find the equilibrium constant equation function of $P_t$ and $x_e$ if $H_2$ is introduced to the

system $($in $CR{H}_2$ is introduce to the reactor to protect the catalyst$)$