Matematika

Pertanyaan

Hitunglah nilai x (jika ada) yang memenuhi persamaan nilai mutlak 1. |4-3x|=|-4| 2. 2x + |3x-8|=4 3. 2x+|3x-8|=-4 4. 5 |2x-3|=2|3-5x| 5. 2x + |8-3x| = |x-4|

1 Jawaban

  • Mapel : Matematika
    Kelas : X SMA
    Bab : Mutlak

    Pembahasan :
    |4 - 3x| = |-4|
    |4 - 3x| = 4

    4 - 3x = 4
    4 - 4 = 3x
    3x = 0
    x = 0

    4 - 3x = -4
    3x = 4 + 4
    3x = 8
    x = 8/3

    Hp : {0 , 8/3}

    ————————————————
    2|3x - 8| = 10
    |3x - 8| = 5

    3x - 8 = 5
    3x = 13
    x = 13/3

    3x - 8 = -5
    3x = 3
    x = 1

    Hp : {1 , 13/3}

    ————————————————
    2x + |8 - 3x| = |x - 4|
    |x - 4| - |8 - 3x| = 2x

    x - 4 - 8 + 3x = 2x
    4x - 12 = 2x
    4x - 2x = 12
    2x = 12
    x = 6

    x - 4 - 8 + 3x = -2x
    4x - 12 = -2x
    4x + 2x = 12
    6x = 12
    x = 2

    Hp : {2 , 6}

    ————————————————
    5|2x - 3| = 2|3 - 5x|
    (10x - 15)² = (6 - 10x)²
    (10x - 15)² - (6 - 10x)² = 0
    (10x - 15 + 6 - 10x)(10x - 15 - 6 + 10x) = 0
    (-9)(20x - 21) = 0
    -180x + 189 = 0
    180x = 189
    x = 189/180
    x = 21/20

    Hp = {21/20}

    ————————————————
    2x + |3x - 8| = -4
    |3x - 8| -4 - 2x
    (3x - 8)² = (-4 - 2x)²
    (3x - 8)² - (-4 - 2x)² = 0
    (x - 12)(5x - 4) = 0
    x = 4/5
    x = 12

    Hp : {4/5 , 12}

    ————————————————
    2x + |3x - 8| = 4
    |3x - 8| = 4 - 2x
    (3x - 8)² = (4 - 2x)²
    (3x - 8)² - (4 - 2x)² = 0
    (x - 4)(5x - 12) = 0
    x = 12/5
    x = 4

    Hp : {12/5 , 4}

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