Question

Помогите по математике срочно!!!!
15 баллов​

Answer 1

$0.9(b - 5) - 0.8(b - 2) = 2.3 \\ 0.9b - 4.5 - 0.8b + 1.6 = 2.3 \\ 0.1b - 2.9 = 2.3 \\ 0.1b = 5.2 \\ b = 52$