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

Toán Lớp 7: ????+1 x+3 x+2 x-4 =– + =– – ==- = == 8 6 7 13 Ai gi

Toán Lớp 7: ????+1 x+3 x+2 x-4
—– + —– – ——- = ——
8 6 7 13
Ai giúp em tìm x thuộc Q với ah

Comments ( 2 )

  1. (x+1)/8 + (x+3)/6 – (x+2)/7 = (x-4)/13
    => (x+1)/8 + (x+3)/6 – (x+2)/7 – (x-4)/13 =0
    => (x+1)/8 + 1 + (x+3)/6 +1 – ( (x+2)/7 + 1) – ( (x-4)/13 +1) =0
    => (x+1)/8 + 8/8 + (x+3)/6 + 6/6 – ( (x+2)/7 + 7/7) – ( (x-4)/13 + 13/13)=0
    => (x+9)/8 + (x+6)/6 – (x+9)/7 – (x+9)/13=0
    => (x+9) ( 1/8+ 1/6 – 1/7 – 1/13)=0
    Vì 1/8+ 1/6 – 1/7 – 1/13 ne 0
    =>x+9=0
    => x=-9
    Vậy x=-9
     

  2. Giải đáp:
    $\\$
    (x+1)/8 + (x+3)/6 – (x+2)/7 = (x-4)/13
    -> (x+1)/8 + (x+3)/6 – (x+2)/7 – (x-4)/13=0
    -> ( (x+1)/8 + 1) + ( (x+3)/6 + 1) – ( (x+2)/7 + 1) – ( (x-4)/13+1) =0
    -> ( (x+1)/8 + 8/8) + ( (x+3)/6 + 6/6) – ( (x+2)/7 + 7/7) – ( (x-4)/13 + 13/13)=0
    -> (x+1+8)/8 + (x+3+6)/6 – (x+2+7)/7 – (x-4+13)/13=0
    -> (x+9)/8 + (x+9)/6 – (x+9)/7 – (x+9)/13=0
    -> (x+9) (1/8 + 1/6 – 1/7 – 1/13)=0
    ->x+9=0 (Vì 1/8 + 1/6 – 1/7 – 1/13 \ne 0)
    ->x=0-9
    ->x=-9
    Vậy x=-9
     

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