(29,3 - x) + 54 = 69,351
(29,3 - x) = 69,351 -54
29,3 - x=15,351
-х=15,351-29,3
-х=-13,949
х=13,949
Проверка
(29,3 - 13,949) + 54 = 69,351
15,351+54=69,351
69,351=69,351
(29,3 - x) + 54 = 69,351
(29,3 - x) = 69,351 -54
29,3 - x=15,351
-х=15,351-29,3
-х=-13,949
х=13,949
Проверка
(29,3 - 13,949) + 54 = 69,351
15,351+54=69,351
69,351=69,351