23. Agar f(x) = (2x + 1) / (3x - 1) bo'lsa, f(1/x) + f(x/9) funksiyani aniqlang.

Разбираемся:

1. Найдем f(1/x) и f(x/9):
   • f(1/x) = (2(1/x) + 1) / (3(1/x) - 1) = (2/x + 1) / (3/x - 1) = (2 + x) / (3 - x)
   • f(x/9) = (2(x/9) + 1) / (3(x/9) - 1) = (2x/9 + 1) / (x/3 - 1) = (2x + 9) / (3x - 9) = (2x + 9) / (3(x - 3))
2. Теперь найдем f(1/x) + f(x/9):
   • f(1/x) + f(x/9) = (2 + x) / (3 - x) + (2x + 9) / (3(x - 3)) = (3(2 + x) - (2x + 9)) / (3(3 - x)) = (6 + 3x - 2x - 9) / (3(3 - x)) = (x - 3) / (3(3 - x)) = -1/3

Ответ: D) -1/3