Matematika

Pertanyaan

Tentukan nilai X yang memenuhi nilai mutlak berikut
a. |4x+3|=7
b. |3x-8|=4
c. 5|2x-1|-4=11
d. 2|3x-6|-2=15
e. 2|x-5|+7=14
f. 4|3x+1|-7=16
g. 3-|4x-5|=-15

1 Jawaban

  • Mapel : Matematika
    Kelas : X SMA
    Bab : Mutlak

    Pembahasan :
    |4x + 3| = 7
    (4x + 3)² - 7² = 0
    (4x + 10)(4x - 4) = 0
    x = -5/2
    x = 1

    Hp : {-5/2 , 1}

    ————————————————
    |3x - 8| = 4
    (3x - 8)² - 4² = 0
    (3x - 12)(3x - 4) = 0
    x = 4
    x = 4/3

    Hp : {4/3 , 4}

    ————————————————
    5|2x - 1| - 4 = 11
    5|2x - 1| = 15
    |2x - 1| = 3
    (2x - 1)² - 3² = 0
    (2x + 2)(2x - 4) = 0
    x = -1
    x = 2

    Hp : {-1 , 2}

    ————————————————
    2|3x - 6| - 2 = 15
    2|3x - 6| = 17
    |3x - 6| = 17/2
    (3x - 6)² - (17/2)² = 0
    (3x - 6 + 17/2)(3x - 6 - 17/2) = 0
    (3x + 5/2)(3x - 29/2) = 0
    x = -5/6
    x = 29/6

    Hp : {-5/6 , 29/6}

    ————————————————
    2|x - 5| + 7 = 14
    2|x - 5| = 7
    |x - 5| = 7/2
    (x - 5)² - (7/2)² = 0
    (x - 5 + 7/2)(x - 5 - 7/2) = 0
    (x - 3/2)(x - 17/2) = 0
    x = 3/2
    x = 17/2

    Hp : {3/2 , 17/2}

    ————————————————
    4|3x + 1| - 7 = 16
    4|3x + 1| = 23
    |3x + 1| = 23/4
    (3x + 1)² - (23/4)² = 0
    (3x + 1 + 23/4)(3x + 1 - 23/4) = 0
    (3x + 27/4)(3x - 19/4) = 0
    x = -9/4
    x = 19/12

    Hp : {-9/4 , 19/12}

    ————————————————
    3 - |4x - 5| = -15
    |4x - 5| = 18
    (4x - 5)² - 18² = 0
    (4x + 13)(4x - 23) = 0
    x = -13/4
    x = 23/4

    Hp : {-13/4 , 23/4}

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