Intouch and Extouch Triangles, Area- ''little'' algebra

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http://gogeometry.blogspot.com/2008/05/geometry-problem-86.html?m=1

In the solution of pr. 86 posted by Anonymous, could anyone please please explain me how to do this ''little'' algebra?

Thank you

 

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Intouch and Extouch Triangles


How to prove that the triangel |EDF| has the same area as triangel |HGM| if I know that:
AF=AE=p-a=BM=CH
BF=BD=p-b=AM=CG
CD=CE=p-c=BG=AH