найди неизвестное
б)26.9 - ? = 104
  ? + 480 : 8 = 570
  68 : 4 + ? = 158
  ? - 7 .18 = 57

26.9 - х = 10.429.9 - 10.4 = хх= 19.5х + 480 : 8 = 570х + 60 = 570 х = 570 - 60х = 51068 : 4 + х = 15817 + х = 158х = 158 - 17х = 141 х - 7.18 = 57х = 57 + 7.18х = 64.18

26.9 - ( - 77,1)= 104510 + 480 : 8 = 57068 : 4 + 141 = 15864,18 - 7 .18 = 57