If x is amount of adsorbate and m is amount of adsorbent, which of the following relations is related to adsorption process

Freundlich adsorption isotherm can be expressed by the equation xm=K P1nThe Langmuir adsorption  isotherm can be expressed by the equation xm=bp1+apAdsorption isotherms and adsorption Isobars are plotted only when either temperature or pressure is kept constant.It can not be plotted when none of the pressure or temperature is constant.