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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: `3/4.x-1/2=3/7+x` `x+5/(2005)+x+6/(2004)+x+7/(2003)=-3`

Tháng Một 19, 2023 Toán học 2 Comments 0 views

Toán Lớp 7: 3/4.x-1/2=3/7+x
x+5/(2005)+x+6/(2004)+x+7/(2003)=-3

Comments ( 2 )

  1. kimnguenoanh
    kimnguenoanh
    19 Tháng Một, 2023 at 9:20 sáng
    Reply
    3/4x – 1/2 = 3/7 + x
    => 3/4x – x = 3/7 + 1/2
    => -1/4x = 13/14
    => x = 13/14 : (-1)/4
    => x = -26/7
    Vậy x= -26/7
    Làm như đề bài trên câu hỏi :
    x + 5/2005 + x + 6/2004 + x + 7/2003 = -3
    => x + x + x  = -3 – 5/2005 – 6/2004 – 7/2003
    => 3x = -(807219149)/(268269802)
    => x = -(807219149)/(268269802) : 3
    => x = -(807219149)/(804809406)
    Vậy x = -(807219149)/(804809406)
    Sửa lại đề :
    (x + 5)/2005 + (x + 6)/2004 + (x + 7)/2003 = -3
    => (x + 5)/2005 + (x + 6)/2004 + (x + 7)/2003 + 3 = 0
    => (x + 5)/2005  + 1 + (x + 6)/2004  + 1 + (x + 7)/2003 + 1 = 0
    => (x+5+2005)/2005 + (x+6+2004)/2004 + (x+7+2003)/2003=0
    => (x+2010)/2005 + (x+2010)/2004 + (x+2010)/2003 = 0
    => (x+2010)(1/2005 + 1/2004 + 1/2003) = 0
    =>x + 2010=0 (do\ 1/2005 + 1/2004 + 1/2003 \ne 0)
    => x = -2010
    Vậy x=-2010

  2. thanhbinh2k5
    thanhbinh2k5
    19 Tháng Một, 2023 at 9:19 sáng
    Reply
    Giải đáp:
    $\\$
    a,
    3/4x – 1/2 = 3/7 + x
    -> 3/4x – 1/2 = x + 3/7
    -> 3/4x – x = 1/2 + 3/7
    -> (3/4 – 1)x = 7/14 + 6/14
    -> (3/4 – 4/4)x = 13/14
    -> (-1)/4x = 13/14
    ->x=13/14 ÷ (-1)/4
    ->x=(-26)/7
    Vậy x=(-26)/7
    $\\$
    b,
    (x+5)/2005 + (x+6)/2004 + (x+7)/2003 = -3
    -> (x+5)/2005 + (x+6)/2004 + (x+7)/2003 +3=0
    -> (x+5)/2005 + (x+6)/2004 + (x+7)/2003+1+1+1=0
    -> ( (x+5)/2005 + 1) + ( (x+6)/2004 + 1) + ( (x+7)/2003+1)=0
    -> ( (x+5)/2005 + 2005/2005) + ( (x+6)/2004  + 2004/2004) + ( (x+7)/2003 + 2003/2003) =0
    -> (x+5+2005)/2005 + (x+6+2004)/2004 + (x+7+2003)/2003=0
    -> (x+2010)/2005 + (x+2010)/2004 + (x+2010)/2003=0
    -> (x+2010) (1/2005 + 1/2004 + 1/2003)=0
    -> x+2010=0 (Do 1/2005 + 1/2004 + 1/2003 \ne 09)
    ->x=0-2010
    ->x=-2010
    Vậy x=-2010
     

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222-9+11+12:2*14+14 = ? ( )

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