12) log₄ log₁₇ 289 - 1/4 log₅ 625 = log₄ log₁₇ 17² - 1/4 log₅ 5⁴ = log₄ 2 - 1/4 * 4 = log₄ 4^(1/2) - 1 = 1/2 - 1 = -1/2
Ответ: -1/2