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

## Toán Lớp 6: 1.-20 < x < 21 2.-18 < x < 17 3.-27 < x ≤ 27 4.│x│≤ 3 │-x│< 5 GIÚP MIK ZỚI:(((((((

Toán Lớp 6: 1.-20 < x < 21 2.-18 < x < 17 3.-27 < x ≤ 27 4.│x│≤ 3 │-x│< 5 GIÚP MIK ZỚI:(((((((

1. 1. x ∈ { -19 ; -18 ; -17 ; … ; 19 ; 20 }
2. x ∈ { -17 ; -16 ; -15 ; … ; 15 ; 16 }
3, x ∈ { -26 ; -25 ; -24 ; … ; 25 ; 26 }
4. x ∈ { -3 ; -2 ; -1 ; … ; 2 ; 3 }
x ∈ { 1 ; 2 ; 3 ; 4 }

2. 1) -20<x<21
=>x∈{-19;-18;-17;….;20}
Vậy x∈{-19;-18;-17;….;20}
2)-18<x<17
=>x∈{-17;-16;-15;…;16}
Vậy x∈{-17;-16;-15;…;16}
3)-27<x<=27
=>x∈{-26;-25;-24;….;27}
Vậy x∈{-26;-25;-24;….;27}
4)|x|<=3
=>|x|∈{…;-2;-1;0;1;2;3}
Mà |x|>=0AAx=>|x|∈{0;1;2;3}
|x|=0=>x=0
|x|=1=> $$\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.$$
|x|=2=> $$\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.$$
|x|=3=> $$\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.$$
Vậy x∈{0;+-1;+-2;+-3}
5)|-x|<5
=>|-x|∈{…;-2;-1;0;1;2;3;4}
|-x|>=0AAx
=>|-x|∈{0;1;2;3;4}
-|x|=0=>x=0
|-x|=1=> $$\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.$$
|-x|=2=> $$\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.$$
|-x|=3=> $$\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.$$
|-x|=4=> $$\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.$$
Vậy x∈{0;+-1;+-2;+-3;+-4}