Matematika

Pertanyaan

nilai x dari sistem persamaan 5x-3y=9 dan -2x-5y=-16

2 Jawaban

  • Kelas 8 Matematika
    Bab SPLDV

    5x - 3y = 9 → dikali 2 → 10x - 6y = 18
    -2x - 5y = -16 → dikali 5 → -10x - 25y = -80

    10x - 6y = 18
    -10x - 25y = -80
    ------------------------ +
    -31y = -62
    y = 2

    5x - 3y = 9
    5x - 3 . 2 = 9
    5x = 9 + 6
    x = 15/5
    x = 3
  • Jawab :

    10x + 6y = 18
    -10x - 25y = -80
    ______________ +
             -31y   = -62
                  y   = 2

    substitusi ke 1

    5x - 3y = 9
    5x - 3(2) = 9
    5x - 6 = 9
    5x      = 9 + 6
    5x      = 15
    x        = 15/5
    x        = 3

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