8. Funksiya f (4x) = 2f(x) - 3 shartni qanoatlantiradi. Agar f(4) = 21 bo'lsa, f() ning qiymatini toping. A) B) 2 C) D)

Let's solve this problem step by step. We are given f(4x) = 2f(x) - 3 and f(4) = 21. We need to find f(1). Let x = 1 in the equation f(4x) = 2f(x) - 3. f(4 * 1) = 2f(1) - 3 f(4) = 2f(1) - 3 We know f(4) = 21, so we substitute this into the equation: 21 = 2f(1) - 3 21 + 3 = 2f(1) 24 = 2f(1) f(1) = 24 / 2 f(1) = 12 However, if the last line in the original question says f(1/4), not f(1), then let x = 1/4 f(4 * (1/4)) = 2f(1/4) - 3 f(1) = 2f(1/4) - 3. Note that f(1) != 21, so we need to find another value of f(x). Let x = 4x'. Then, f(4x) = 2f(x) - 3 => f(x) = 2f(x/4) - 3 So, f(4) = 21. Apply the rule to derive f(1). f(1) = 2f(1/4) - 3, therefore: f(1/4) = (f(1)+3) / 2 and f(1) is unknown. From f(4) = 21 => 21 = 2f(1) - 3, f(1) = 12. From f(1/4) = (f(1)+3)/2 = (12+3)/2 = 15/2 = 7.5. Then f(1/4) = 15/2

Ответ: 15/2

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