Matematika

Pertanyaan

NO NGASAL ASAL!!!

Nilai y + [tex] \sqrt{x^2 - 2xz+z^2} [/tex] dari sistem persamaan :
[tex] y + \dfrac{2}{x+z} = 4 \\\\ 5y + \dfrac{18}{2x+y+z} = 18 \\\\ \dfrac{8}{x+z} - \dfrac{6}{2x + y+z} = 3 [/tex]

adalah ...

1 Jawaban

  • [tex] y + \frac{2}{x + z } = 4 \\
    \frac{2}{x + z } = 4 - y \ ... (i) [/tex]

    [tex] 5y + \frac{18}{2x+y+z} = 18 \\
    \frac{18}{2x+y+z} = 18 - 5y \\
    \frac{3 \cdot 6}{2x + y + z} = 18 - 5y \\
    \frac{6}{2x + y + z} = 6 - \frac53y \ ... (ii) [/tex]

    [tex] Didapat \ : \\
    \frac{8}{x + z} - \frac{6}{2x + y + z} = 3 \\
    4 (\frac{2}{x + z}) - \frac{6}{2x + y + z} = 3 \\
    Subtitusi \ persamaan \ (i) \ dan \ (ii) \ : \\
    4(4 - y) - (6 - \frac53y) = 3 \\
    16 - 4y - 6 + \frac53y = 3 \\
    - \frac73y = - 7 \\
    y = 3 \ ... (iii) [/tex]

    Subtitusikan persamaan (iii) ke (i)
    [tex] \frac{2}{x + z } = 4 - y \\
    \frac{2}{x + z } = 4 - 3 \\
    \frac{2}{x + z } = 1 [/tex]
    x + z = 2 ... (iv)

    Subtitusikan persamaan (iii) ke (ii)
    [tex] \frac{6}{2x + y + z} = 6 - \frac53y \\
    \frac{6}{2x + 3 + z} = 6 - \frac53 \times 3 \\
    \frac{6}{2x + 3 + z} = 1 [/tex]
    6 = 2x + 3 + z
    2x + z = 3 ... (v)

    Eliminasi persamaan (iv) dan (v)

    x + z = 2
    2x + z = 3
    ––––––– (–)
    -x = -1
    x = 1

    Subtitusikan x = 1 ke persamaan (iv)
    x + z = 2
    1 + z = 2
    z = 1

    Didapat x = 1 , y = 3 , z = 1

    Maka :
    [tex] y + \sqrt{x^2 - 2xz + z^2} \\
    = y + \sqrt{ (x - z)^2 } [/tex]
    = y + |x - z|
    = 3 + |1 - 1|
    = 3

    koreksi jika ada kesalahan

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