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

Toán Lớp 6: 2 2x + 1 1 ________= ___________ ( x khác __ ) 2x+1 18 2

Toán Lớp 6: 2 2x + 1 1
________= ___________ ( x khác __ )
2x+1 18 2

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    x\ne1/2
    Ta có:
    2/(2x+1)=(2x+1)/18
    →(2x+1).(2x+1)=2.18
    →(2x+1)^2=36
    →(2x+1)^2=6^2
    →|2x+1|=6
    TH 1:
    2x+1=6
    →2x=6-1
    →2x=5
    →x=5/2(TM)
    TH 2:
    2x+1=-6
    →2x=-6-1
    →2x=-7
    →x=-7/2(TM)
    Vậy x=5/2 hoặc x=-7/2

  2. 2/( 2x + 1 ) = ( 2x + 1 )/18
    ⇔ ( 2x + 1 ) . ( 2x + 1 ) = 2 . 18
    ⇔ ( 2x + 1 )^2 = 36
    ⇔ \(\left[ \begin{array}{l}( 2x + 1 )² = 6²\\( 2x + 1 )² = ( – 6 )²\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}2x + 1 = 6\\2x + 1 = – 6\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}2x = 5\\2x = – 7\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}x = \frac{5}{2} \\x = \frac{- 7}{2}\end{array} \right.\) 
    Vậy , x ∈ { 5/2 ; ( – 7 )/2 } .

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