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

Toán Lớp 7: tìm x ạ | x+1 | + x = 3

Toán Lớp 7: tìm x ạ
| x+1 | + x = 3

Comments ( 2 )

  1. $@Shinn$
    |x+1|+x=3
    x+1+x=3
    x+x=3-1
    2x=2
    Vì x có dấu giá trị tuyệt đối nên :
    * 2x=2             
    x=1
    * 2x=-2
    x=-1
    Vậy x ∈ {1;-1}
     

  2. $| x+1 | + x = 3$    $ĐKXĐ:x≤3$
    $<=>| x+1 |=3-x$
    $<=>\left[\begin{matrix} x+1=3-x\\ x+1=x-3\end{matrix}\right.$
    $<=>\left[\begin{matrix} x=1\\ x∈\emptyset\end{matrix}\right.$
    Vậy $x=1$
     

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