54x - 27 x = 81
(54-27)x = 81
27x = 81
x = 81/27
x = 3
Проверка:
54 * 3 - 27 * 3 = 81
162 - 81 = 81
81 = 81
14x + x - 9x + 2 = 56
6x + 2 = 56
6x = 54
x = 54 / 6
x = 9
Проверка:
14 * 9 + 9 - 9 * 9 + 2 = 56
126 + 9 - 81 + 2 = 56
45 + 9 + 2 = 56
56 = 56