Matematika

Pertanyaan

penyelesaian persamaan 9log x- xlog3=1/2

1 Jawaban

  • Bab Logaritma
    Matematika SMA Kelas X 

    ^ = pangkat

    ⁹log x - ˣlog 3 = 1/2
    1/(ˣlog 9) - ˣlog 3 = 1/2
    1/(ˣlog 3²) - ˣlog 3 = 1/2
    1/(2 . ˣlog 3) - ˣlog 3 = 1/2

    ˣlog 3 = p

    1/(2p) - p = 1/2

    **semua dikalikan 2p**

    1 - 2p² = p
    2p² + p - 1 = 0
    (2p - 1) (p + 1) = 0
    2p - 1 = 0
    2p = 1
    p = 1/2

    p + 1 = 0
    p = -1

    ˣlog 3 = 1/2
    x^(1/2) = 3
    (x^(1/2))² = 3²
    x = 9

    ˣlog 3 = -1
    x⁻¹ = 3
    x⁻¹ = (1/3)⁻¹
    x = 1/3

    jadi, x = 1/3 atau x = 9

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