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

Toán Lớp 6: -7(3x – 5) + 2(7x – 14) = 28 giải thích nhanh

Toán Lớp 6: -7(3x – 5) + 2(7x – 14) = 28 giải thích nhanh

Comments ( 2 )

  1. Giải đáp:
     $\text{-7.(3x-5)+2.(7x-14)=28}$
    $\text{⇔-21x+35+14x-28=28}$
    $\text{⇔(14x-21x)+(35-28)=28}$
    $\text{⇔-7x+7=28}$
    $\text{⇔-7x= 21}$
    $x= -3$
     $Vậy$ $x= -3$

  2. -7(3x – 5) + 2(7x – 14) = 28
    -21x+35+14x-28=28
    -21x+14x+35-56=0
    -21x+14x-21=0
    -7x-21=0
    -7(x+3)=0
    x+3=0
    x=-3
     

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