Bài 1:Tìm x;biết: a,x=-15/21:2 b,2/3.x+4,5=0 c,x+1/19+x+2/18+x+3/17=x+4/16+x+5/15+x+6/14

Question

Bài 1:Tìm x;biết:
a,x=-15/21:2
b,2/3.x+4,5=0
c,x+1/19+x+2/18+x+3/17=x+4/16+x+5/15+x+6/14

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Isabelle 2 tháng 2021-07-25T21:50:38+00:00 1 Answers 2 views 0

Answers ( )

    0
    2021-07-25T21:52:17+00:00

    a, x=-15/21:2

    x=-15/21*1/2

    x=-15/42=-5/14

    b,

    2/3*x+4,5=0

    2/3*x       =0-4,5

    x              =-4.5 : 2/3

    x              =-4.5/1*3/2

    x             = -27/4=-6,75

    c,

    x+1/19+x+2/18+x+3/17=x+4/16+x+5/15+x+6/14

    =x+1/19+x+2/18+x+3/17+x+4/16+x+5/15+6/14

    <=>((x+1/19+x+2/18+x+3/17+3))=((x+4/16+x+5/15+x+6/14+3))

    <=>((x+1/19+1)+(x+2/18+1)+(x+3/17+1))-((x+4/16+1)+(x+5/15+1)+(x+6/14+1))=0

    <=>((x+1/19+19/19)+(x+2/18+18/18)+(x+3/17+17/17))((x+4/16+16/16)+(x+5/15+15/15)+(x+6/14+14/14))=0

    <=>(x+20/19+x+20/18+x+20/17)-(x+20/16+x+20/15+x+20/14)=0

    <=>(x+20)*(1/19+1/18+1/17-1/16-1/15-1/14)=0

    vì 1/19+1/18+1/17-1/16-1/15-1/14 khác 0

    =>x+20=0

    =>x=-20

    dấu ngoặc tròn tui để in đậm và nghiêng thực ra là dấu ngoặc vuông nhaaa :>

     

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