Matematika

Pertanyaan

selesaikan sistem persamaan linear tiga variabel berikut!
2x+y-z=2
x+2y+3z= 13
3x-y+z=8

1 Jawaban

  • 2x + y - z = 2 |×1
    x + 2y + 3z = 13 |×2
    2x + y - z = 2
    2x + 4y + 6z = 26
    --------------------------(-)
    - 3y - 7z = - 24 ...pers 1

    x + 2y + 3z = 13 |×3
    3x - y + z = 8
    3x + 6y + 9z = 39
    3x - y + z = 8
    ---------------------------(-)
    7y + 8z = 31 ... pers 2

    pers 1 & 2
    - 3y - 7z = - 24 |×7
    7y + 8z = 31 |×3
    - 21y - 49z = - 168
    21y + 24z = 93
    ---------------------------(+)
    - 25z = - 75
    z = 3

    - 3y - 7z = - 24
    - 3y - 7(3) = - 24
    - 3y = - 24 + 21
    - 3y = - 3
    y = 1

    2x + y - z = 2
    2x + 1 - 3 = 2
    2x = 2 + 2
    x = 4 ÷ 2
    x = 2

    Hp = { 2,1,3}

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