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