6(с*9)=36.936
54с=36.936
с=36.936:54
с=684
21851-а*7=16.188
а*7=21.851-16.188
а*7=5.663
а=5.663:7
а=809
6(с*9)=36.936
54с=36.936
с=36.936:54
с=684
21851-а*7=16.188
а*7=21.851-16.188
а*7=5.663
а=5.663:7
а=809