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

Toán Lớp 8: tìm x: a) (x-2012) –x+2012 =0 b) x(2011+x)-x-2011=0

Toán Lớp 8: tìm x: a) (x-2012) –x+2012 =0
b) x(2011+x)-x-2011=0

Comments ( 2 )

  1. a, (x-2012) – x+2012=0
    (x-2012)- (x-2012) =0
    0=0
    b, x(2011 + x) – x -2011=0
    x(2011+x) – (2011 +x) =0
    (2011+x)(x-1)=0
    =>\(\left[ \begin{array}{l}2011+x=0\\x-1=0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=-2011\\x=1\end{array} \right.\) 
    \text{Vậy} x ∈ { -2011;1}

  2. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    a) (x-2012)-x+2012=0
    =x-2012-x+2012=0
    =(x-x)+(-2012+2012)=0
    Vậy 0=0 ( ko bt có sai đề ko ạ)
    b)  x(2011+x)-x-2011=0
      = x(2011+x)-(x+2011)=0
      = x(x+2011)-(x+2011)=0
    = (x-1)(x+2011)=0
    ⇒ x-1=0
           x=1
    ⇒ x+2011=0
          x=-2011
    Vậy x=1 hoặc x=-2011

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