To start you should recall from the tetrahedron of state that formula_59starting with equation 2, you can rearrange it so that formula_60. formula_61 can be substituted for equation 4, while in equation 4, formula_62 can be replaced by formula_63due to equation 3, which can then be replaced by equation 5. formula_64 can likewise be replaced using equation 7, in which formula_65can be replaced with formula_66 which can then be replaced with equation 10. Following these substituted yields the first state equation which is shown below.