Matematika

Pertanyaan

Linier 3 variable.
2x+y-z=5
x-y+z=-2
3x+2y+4z=3

2 Jawaban

  • 2x + y - z = 5
    x -y + z = -2
    ---------------+
    3x = 3
    x = 1

    1 -y + z = -2 3 + 2y + 4z = 3
    -y + z = -3 ( x 4) 2y + 4z = 0

    2y + 4z = 0
    -4y + 4z = -12
    -------------- -
    6y = 12
    y = 2
    x-y+z = -2
    1-2 + z = -2
    -1 + z = -2
    z = -1


  • eliminasi pers (1) dan (2)
    2x +y-z = 5
     x -y+z=-2
    3x      = 3
            x= 3: 3
            x= 1

    eliminasi pers (1) dan (3)
    2x + y - z = 5-------------> dikali 2
    3x +2y+4z= 3-------------> dikali 1
    maka :
    4x + 2y - 2z = 10
    3x + 2y + 4z= 3
      x         -6z = 7...........(*)

    eliminasi pers (2) dan (3)
    x - y + z  = -2---------------> dikali 2
    3x+2y+4z= 3----------------> dikali 1
    maka :
    2x - 2y + 2z = -2
    3x + 2y+ 4z = 3
    5x        + 6z = 1................(**)

    substitusi x = 1 ke pers (*)
    1 - 6z = 7
        -6z = 6
           z = -1

    substitusi x=1, z=-1 ke pers (1)
    2x + y - z =5
    2(1)+y-(-1)= 5
    2 + y + 1 = 5
    3 + y = 5
          y = 2

    Maka HP = {1, 2, -1}

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