(4 1/9-а)+8 5/9=9 2/9
4 1/9-а=9 2/9-8 5/9
4 1/9-а=6/9
а=4 1/9-6/9
а=34/9
5 3/7-(в-2 1/7)=2 4/7
в-2 1/7=5 3/7-2 4/7
в-2 1/7=2 6/7
в=2 1/7+2 6/7
в=4 7/7
в=5
500-400:(х+43)=495
400:(х+43)=500-495
400:(х+43)=5
х+43=400:5
х+43=80
х=80-43
х=37
(270:у-12)*70=1260
(270:у-12)=1260:70
(270:у-12)=18
270:у=18+12
270:у=30
у=270:30
у=9