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

Toán Lớp 7: |x+1|=|x-3| Giải giúp mình vs ạ

Toán Lớp 7: |x+1|=|x-3|
Giải giúp mình vs ạ

Comments ( 2 )

  1. Ta có: |x+1|=|x-3| => \(\left[ \begin{array}{l}x+1 = x-3\\x+1 = -x+3\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x-x = -3-1\\x+x =3-1\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}0.x =-4\\2.x = 2\end{array} \right.\)  ( Vô lí)
    =>\(\left[ \begin{array}{l}0.x =-4\\x = 1\end{array} \right.\)  
    Vậy x ….
    Xin hay nhất nhé 🙂

  2. |x+1|=|x-3|
    ⇒\(\left[ \begin{array}{l}x+1=x-3\\x+1=-(x-3)\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}x+1=x-3\\x+1=-x+3\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}x-x=-3-1\\x+x=3-1\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}0x=-4\text{(vô lý)}\\x+x=3-1\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}0x=-4\text{(vô lý)}\\2x=2\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}0x=-4\text{(vô lý)}\\x=1\end{array} \right.\) 
    Vậy x∈{1}.

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