Can someone please explain this example

This is example is taken from chemical engineering thermodynamics by smith

Example 11.2 Property changes of mixing and excess properties are related. Show how Figs. 10.3 and 11.3 are generated from correlated data for H(x) and GE(x). Solution 11.2 With H(x) and GE(x) given, Eqs. (11.7) and (10.86) provide: HE=HandSE=THEGE These allow completion of Fig. 10.3. Property changes of mixing S and G follow from SE and GE by applying Eqs. (11.8) and (11.9): S=SERixilnxiG=GE+RTixilnxi These permit the completion of Fig. 11.3