Fโก(a,12+a;32โˆ’2โขa;โˆ’13)=(89)โˆ’2โขaโขฮ“โก(43)โขฮ“โก(32โˆ’2โขa)ฮ“โก(32)โขฮ“โก(43โˆ’2โขa).