Matematika

Pertanyaan

tolong ya bantu aku"please" pake cara...nomor 3 dan 4
.
yang nomor 3 itu soalnya 3x+4y=10 dan 4x-5y=34
tolong ya bantu akuplease pake cara...nomor 3 dan 4 . yang nomor 3 itu soalnya 3x+4y=10 dan 4x-5y=34

1 Jawaban

  • Metode : Substitusi

    3. 3x+4y = 10 dan 4x-5y = 34

    3x+4y = 10
    3x = 10-4y
    x = 10/3-4/3y

    4x-5y = 34
    4(10/3-4/3y) -5y = 34
    40/3 -16/3y -5y = 34
    -16/3y-15/3y = 102/3-40/3
    -31/3y = 62/3
    -31y = 62
    y = 62/-31
    y = -2

    3x+4y = 10
    4y = 10-3x
    y = 10/4-3/4x

    4x-5y = 34
    4x -5(10/4-3/4x) = 34
    4x -50/4 + 15/4x = 34
    16/4x+15/4x = 136/4+50/4
    31/4x = 186/4
    31x = 186
    x = 186/31
    x = 6

    Metode : Campuran

    3x+4y = 10 (dikali 4)
    4x-5y = 34 (dikali 3)
    ------------------------
    12x+16y = 40
    12x-15y = 102
    --------------(dikurang)
    31y = -62
    y = -62/31
    y = -2

    3x+4y = 10
    3x+4(-2)= 10
    3x-8 = 10
    3x = 10+8
    3x = 18
    x = 18/3
    x = 6