Matematika

Pertanyaan

2x - y = 7000 x + 2y = 1000 5x - 2y =.....? tolong di jawab sekarang

2 Jawaban

  • 2x - y = 7000
    x + 2y = 1000, x = 1000 - 2y
    5x - 2y =.....?

    2 (1000 - 2y) - y = 7000
    2000 - 4y - y = 7000
    2000 - 5y = 7000
    - 5y = 5000
    y = - 1000

    x = 1000 - 2 (-1000)
    x = 1000 + 2000
    x = 3000


    5x - 2y =.....?
    5 (3000) - 2(-1000) = 15000 + 2000
    = 17000
  • 2x - y = 7000
    x + 2y = 1000
    (dikali 2 setiap persamaan) 

    2x - y = 7000
    2x + 4y = 2000 
    (dieliminasi) 
    -5y = 5000
    y = 5000 : -5 = -1000
    jadi, y = -1000

    (ambil satu persamaan)

    2x - y = 7000
    (subtitusikan y = -1000)
    Jadi, 2x - (-1000) = 7000
     
    2x + 1000 = 7000
    2x = 7000 - 1000
    2x = 6000
    x =  3000

    jadi nilai x = 3000

    nilai 5x - 2y = 5(3000) - 2(-1000) = 15000 - (-2000) = 15000 + 2000 = 17000 

Pertanyaan Lainnya