tolong di jawab ya nomer 6 dan 8,beserta caranya
Matematika
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Pertanyaan
tolong di jawab ya nomer 6 dan 8,beserta caranya
1 Jawaban
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1. Jawaban hendrisyafa
6) ⁵Log 3. ³Log (x²+1) = ⁵Log (x+21)
⁵Log (x²+1) = ⁵Log (x+21)
x²+1 = x+21
x²-x-20 = 0
(x+4)(x-5) = 0
x = -4 dan x = 5
hp {x = -4 dan x = 5}
8) Log (x²-24) = log x +log (16/15)⁷+ log (25/24)⁵+ log (81/80)³
= log x + Log (16/15)⁷.(25/24)⁵.(81/80)³
= log x + log (2⁴/3.5)⁷. (5²/2³.3)⁵.(3⁴/2⁴.5)³
= log x + log (2²⁸/3⁷.5⁷) (5¹⁰/2¹⁵.3⁵).(3¹²/2¹².5³)
= log x + log (2²⁸/2²⁷. 3¹²/3¹².5¹⁰/5¹⁰)
= log x + Log 2
= log 2x
x²-24 = 2x
x²-2x-24 = 0
(x-6)(x+4) = 0
x= 6 dan x = -4
hp {x = 6}