Matematika

Pertanyaan

2/x+1/y=2
4/y+3/z=5
3/x+2/3=3
nilai 1/x+/1y+1/y=

1 Jawaban

  • Misal 1/x = a, 1/y = b, 1/z = c

    Persamaan menjadi
    2a + b = 2 (i)
    4b + 3c = 5 (ii)
    3a + 2c = 3 (iii)

    Eliminasi i dan ii

    2a + b = 2 |x 4|
    =>8a + 4b = 8
    =>4b + 3c = 5
    --------------------- (-)
    8a - 3c = 3 (iv)

    Eliminasi iv dan iii
    8a - 3c = 3 |x 2|
    3a + 2c = 3|x 3|

    16a - 6c = 6
    9a + 6c = 9
    --------------- (+)
    25a = 15
    a = 15/25
    a = 3/5

    3a + 2c = 3
    3(3/5) + 2c = 3
    2c = 3 - 15/3
    c = 6/5 : 2
    c = 3/5

    2a + b = 2
    2(3/5) + b = 2
    b = 2 - 6/5
    b = 4/5

    1/x + 1/y + 1/z
    =>a + b + c
    =>3/5 + 4/5 + 3/5
    =>10/5
    =>2

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