а.((77+3а)х16-24):8=271
(77+3а)х16-24=271*8
(77+3а)х16-24=2168
(77+3а)х16=2168+24
(77+3а)х16=2192
77+3а=2192:16
77+3а=137
3а=137-77
3а=60
а=60:3
а=20
б.((2m+6+7m):11+13)+54=70
(2m+6+7m):11+13=70-54
(2m+6+7m):11+13=16
(2m+6+7m):11=16-13
(2m+6+7m):11=3
2m+6+7m=3*11
2m+6+7m=33
9m+6=33
9m=27
m=3