Matematika

Pertanyaan

4x-3y+2z=8
3x+2y-4z=9
2x+3y+4z=16

2 Jawaban

  • 4x - 3y + 2z = 8 ..... (1)
    3x + 2y - 4z = 9 ..... (2)
    2x + 3y + 4z = 16 .... (3)

    Eliminasi (1) dan (2)
    4x - 3y + 2z = 8 |.2| 8x - 6y + 4z = 16
    3x + 2y - 4z = 9 |.1| 3x + 2y - 4z = 9
    ---------------------------------------------------- +
    ................................... 11x - 4y = 25 .... (4)

    Eliminasi (2) dan (3)
    3x + 2y - 4z = 9
    2x + 3y + 4z = 16
    ------------------------ +
    5x + 5y = 25 (bagi 5)
    x + y = 5 ............ (5)

    Eliminasi (4) dan (5)
    11x - 4y = 25 |.1| 11x - 4y = 25
    x + y = 5 |kali 4| 4x + 4y = 20
    ----------------------------------------- +
    ............................. 15x = 45 => x = 45/15 => x = 3

    Substitusi x = 3 ke (5)
    x + y = 5
    3 + y = 5
    y = 5 - 3
    y = 2

    Substitusi x = 3, y = 2 ke (1)
    4x - 3y + 2z = 8
    4(3) - 3(2) + 2z = 8
    12 - 6 + 2z = 8
    6 + 2z = 8
    2z = 8 - 6
    2z = 2
    z = 1

    HP = {(3, 2, 1)}
  • Kelas : X SMA
    Pelajaran : Matematika
    Kategori : Sistem Persamaan Linear Tiga Variabel
    Kata kunci : SPLTV

    Penjelasan :

    4x - 3y + 2z = 8 .... pers I
    3x + 2y - 4z = 9 .... pers II
    2x + 3y + 4z = 16 .... pers III

    eliminasi z dari pers I dan II

    4x - 3y + 2z = 8 |×2|
    3x + 2y - 4z = 9 |×1|

    8x - 6y + 4z = 16
    3x + 2y - 4z = 9
    ------------------------- +
    11x - 4y = 25 ..... pers IV

    eliminasi z dari pers II dan III

    3x + 2y - 4z = 9
    2x + 3y + 4z = 16
    ------------------------ +
    5x + 5y = 25 ..... pers V

    eliminasi y dari pers IV dan V

    11x - 4y = 25 |×5|
    5x + 5y = 25 |×4|

    55x - 20y = 125
    20x + 20y = 100
    ---------------------- +
    75x = 225
    x = 225/75
    x = 3

    subtitusikan x = 3 ke dalam pers IV

    11x - 4y = 25
    11(3) - 4y = 25
    33 - 4y = 25
    -4y = 25 - 33
    -4y = -8
    y = -8/-4
    y = 2

    subtitusikan x = 3 dan y = 2 ke dalam pers III

    2x + 3y + 4z = 16
    2(3) + 3(2) + 4z = 16
    6 + 6 + 4z = 16
    12 + 4z = 16
    4z = 16 - 12
    4z = 4
    z = 4/4
    z = 1

    HP = {(3 , 2 , 1)}

    semoga membantu

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