12b + 7(b+4) = 26 - 4b12b + 7b + 28 = 26 - 4b19b + 28 = 26 - 4b19b + 4b = 26 - 2823b = -2b = -2 / 23
Ответ: b = -2 / 23
12b + 7(b+4) = 26 - 4b
12b + 7b + 28 = 26 - 4b
19b + 28 = 26 - 4b
19b + 4b = 26 - 28
23b = -2
b = -2 / 23
Ответ: b = -2 / 23