Matematika

Pertanyaan

2x + 5y = 20 dan x + 4y = 10 berapakah 3x + 2y ?

2 Jawaban

  • Bab Persamaan Linear
    Matematika SMP Kelas VIII

    x + 4y = 10
    x = 10 - 4y

    2x + 5y = 20
    2(10 - 4y) + 5y = 20
    20 - 8y + 5y =20
    -3y = 20 - 20
    y = 0

    x = 10 - 4y
    x = 10 - 4 . 0
    x = 10

    3x + 2y = 3 . 10 + 2 . 0 = 30
  • 2x + 5y = 20 | * 4
      x + 4y = 10 | * 5

    8x + 20y = 80
    5x + 20y = 50
    ------------------- -
    3x           = 30
                x = 30/3
                x = 10

    2(10) + 5y = 20
    5y = 20-20
      y = 0/5
      y = 0

    3x + 2y
    3(10) + 2(0)
    30 + 0
    Jawaban = 30

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