Câu hỏi 179
Tìm các số thực $x$, $y$, $z \gt 0$ sao cho
$$
xyz \le \min \left\{ 4 \left(x - \frac{1}{y}\right), 4 \left(y - \frac{1}{z}\right), 4 \left(z - \frac{1}{x}\right) \right\}.
$$
$$
xyz \le \min \left\{ 4 \left(x - \frac{1}{y}\right), 4 \left(y - \frac{1}{z}\right), 4 \left(z - \frac{1}{x}\right) \right\}.
$$