Matematika

Pertanyaan

Nilai Mutlak

1.) |3x+5| = |2x+20|
2.) |5/x-1| = 1/2
3.) Akar x^2-4x+4 = |2x+3| (pakai sifat |A|^2= (A)^2

1 Jawaban

  • Mapel : Matematika
    Kelas : X SMA
    Materi : Persamaan Mutlak

    Pembahasan :
    |3x + 5| = |2x + 20|
    (3x + 5)² = (2x + 20)²
    (3x + 5)² - (2x + 20)² = 0
    (3x + 5 + 2x + 20)(3x + 5 - 2x - 20) = 0
    (5x + 25)(x - 15) = 0
    x = -5
    x = 15

    Hp : {-5 , 15}

    ————————————————
    |5 / x - 1| = 1/2
    |x - 1| = 2|5|
    |x - 1| = 10
    (x - 1)² = 10²
    (x - 1)² - 10² = 0
    (x - 1 + 10)(x - 1 - 10) = 0
    (x + 9)(x - 11) = 0
    x = -9
    x = 11

    Hp : {-9 , 11}

    ————————————————
    √(x² - 4x + 4) = |2x + 3|
    √(x - 2)² = |2x + 3|
    x - 2 = |2x + 3|
    (2x + 3)² = (x - 2)²
    (2x + 3)² - (x - 2)² = 0
    (2x + 3 + x - 2)(2x + 3 - x + 2) = 0
    (3x + 1)(x + 5) = 0
    x = -1/3
    x = -5

    Hp : {-5 , -1/3}

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