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

Toán Lớp 6: tìm các số nguyên x , biết a, /x – 8 / + 2x – 4 = 0 b, / x+5/ – ( x + 5 ) = 0 c, / 2x -4 / + 3x = 6 d, 2 – x = – /2 -x / e, /x+7/- 2x

Toán Lớp 6: tìm các số nguyên x , biết
a, /x – 8 / + 2x – 4 = 0
b, / x+5/ – ( x + 5 ) = 0
c, / 2x -4 / + 3x = 6
d, 2 – x = – /2 -x /
e, /x+7/- 2x + 3
f, 3 < /x -1/ < 8 mấy bạn giúp mình với

Comments ( 1 )

  1. a) /x-8/+2x-4=0
    ⇔/x-8/=4-2x
    ⇔\(\left[ \begin{array}{l}x-8=4-2x\\x-8=-4+2x\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}3x=12\\-x=4\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x=4\\x=-4(loại)\end{array} \right.\) 
    b)/x+5/-(x+5)=0
    ⇔/x+5/=x+5
    ⇔\(\left[ \begin{array}{l}x+5=x+5\\x+5=-x-5\end{array} \right.\) 
    ⇔2x=-10
    ⇔x=-5(loại) Vậy phương trình vô nghiệm
    c)/2x-4/+3x=6
    ⇔/2x-4/=6-3x
    ⇔\(\left[ \begin{array}{l}2x-4=6-3x\\2x-4=-6+3x\end{array} \right.\)
    ⇔x=2
    d)2-x=-/2-x/
    ⇔\(\left[ \begin{array}{l}2-x=-2+x\\2-x=2-x\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\) 
    ⇔x=2
    e, /x+7/- 2x = 3
    ⇔/x+7/=3+2x
    ⇔\(\left[ \begin{array}{l}x+7=3+2x\\x+7=-3-2x\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x=4\\x=\frac{-10}{3} \end{array} \right.\) 
    f)3</x-1/<8
    ⇒3</x-1/
    ⇒⇔\(\left[ \begin{array}{l}3<x-1\\-3<x-1\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}4<x\\-2<X\end{array} \right.\) 
    ⇔4<x (1)
    ⇒/x-1/<8
    ⇔\(\left[ \begin{array}{l}x-1<8\\x-1<-8\end{array} \right.\) 
    ⇔\(\left[ \begin{array}{l}x<9\\x<-7(loại)\end{array} \right.\) (2)
    Vậy 4<x<9

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