9) logo,2(2x - 3) + logo, 2 7 = logo, 28;

9) log_0.2(2x - 3) + log_0.2 7 = log_0.2 28

Используем свойство логарифмов: log_a b + log_a c = log_a (b*c)

log_0.2((2x - 3) * 7) = log_0.2 28

7(2x - 3) = 28

2x - 3 = 4

2x = 7

x = 3.5

Проверка:

log_0.2(2*3.5 - 3) + log_0.2 7 = log_0.2 28

log_0.2(7 - 3) + log_0.2 7 = log_0.2 28

log_0.2(4) + log_0.2 7 = log_0.2 28

log_0.2(4 * 7) = log_0.2 28

log_0.2 28 = log_0.2 28

Ответ: x = 3.5