Matematika

Pertanyaan

3^x+ 3^5-x = 36 ..tolong bantu jawab ya kak :)

2 Jawaban

  • jawab

    3ˣ + 3⁵⁻ˣ = 36
    3ˣ + 3⁵.3⁻ˣ = 36

    misalkan 3ˣ = a

    a + 243/a = 36....kalikan a
    a² + 243 = 36a
    a² - 36 a + 243 = 0
    (a - 27)(a - 9) = 0
    a = 27  atau a = 9

    3ˣ = a
    a= 27  → 3ˣ = 27 = 3³
    x = 3

    a= 9  → 3ˣ = 9 = 3²
    x  = 2

    HP x = (2, 3)
  • 3ˣ + 3⁵⁻ˣ = 36
    3ˣ + 3⁵ . 3⁻ˣ = 36  (kalikan dengan 3ˣ)
    3²ˣ + 3⁵ = 36 . 3ˣ
    3²ˣ - 36. 3ˣ + 243 = 0

    misalkan
    y = 3ˣ , maka
    y² - 36y + 243 = 0
    (y - 9)(y - 27) = 0
    y = 9    y = 27

    (i)
    y = 9
    3ˣ = 9
    x = 2

    (ii)
    y = 27
    3ˣ = 27
    x = 3

    jadi HP = {2 , 3}

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