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2-x-2-6-




Question Number 159683 by SAMIRA last updated on 20/Nov/21
2 ≤ ∣x−2∣ ≤ 6
$$\mathrm{2}\:\leqslant\:\mid\boldsymbol{{x}}−\mathrm{2}\mid\:\leqslant\:\mathrm{6} \\ $$
Commented by tounghoungko last updated on 20/Nov/21
 ∣x−2∣≥2 ∧ ∣x−2∣ ≤ 6  ⇒(x−2−2)(x−2+2)≥ 0 ∧ (x−2−6)(x−2+6)≤ 0  ⇒(x−4)x ≥ 0 ∧ (x−8)(x+4)≤ 0  ⇒[x≤ 0 ∪ x≥ 4 ] ∧ [−4 ≤ x ≤ 8 ]  ⇒ −4 ≤ x ≤ 0 ∪ 4 ≤ x ≤ 8
$$\:\mid{x}−\mathrm{2}\mid\geqslant\mathrm{2}\:\wedge\:\mid{x}−\mathrm{2}\mid\:\leqslant\:\mathrm{6} \\ $$$$\Rightarrow\left({x}−\mathrm{2}−\mathrm{2}\right)\left({x}−\mathrm{2}+\mathrm{2}\right)\geqslant\:\mathrm{0}\:\wedge\:\left({x}−\mathrm{2}−\mathrm{6}\right)\left({x}−\mathrm{2}+\mathrm{6}\right)\leqslant\:\mathrm{0} \\ $$$$\Rightarrow\left({x}−\mathrm{4}\right){x}\:\geqslant\:\mathrm{0}\:\wedge\:\left({x}−\mathrm{8}\right)\left({x}+\mathrm{4}\right)\leqslant\:\mathrm{0} \\ $$$$\Rightarrow\left[{x}\leqslant\:\mathrm{0}\:\cup\:{x}\geqslant\:\mathrm{4}\:\right]\:\wedge\:\left[−\mathrm{4}\:\leqslant\:{x}\:\leqslant\:\mathrm{8}\:\right] \\ $$$$\Rightarrow\:−\mathrm{4}\:\leqslant\:{x}\:\leqslant\:\mathrm{0}\:\cup\:\mathrm{4}\:\leqslant\:{x}\:\leqslant\:\mathrm{8}\: \\ $$
Answered by gsk2684 last updated on 20/Nov/21
2≤∣x−2∣≤6  2≤(x−2)≤6 if x≥2   4≤x≤8    2≤(2−x)≤6 if x≤2   0≤−x≤4  −4≤x≤0
$$\mathrm{2}\leqslant\mid{x}−\mathrm{2}\mid\leqslant\mathrm{6} \\ $$$$\mathrm{2}\leqslant\left({x}−\mathrm{2}\right)\leqslant\mathrm{6}\:{if}\:{x}\geqslant\mathrm{2}\: \\ $$$$\mathrm{4}\leqslant{x}\leqslant\mathrm{8} \\ $$$$ \\ $$$$\mathrm{2}\leqslant\left(\mathrm{2}−{x}\right)\leqslant\mathrm{6}\:{if}\:{x}\leqslant\mathrm{2}\: \\ $$$$\mathrm{0}\leqslant−{x}\leqslant\mathrm{4} \\ $$$$−\mathrm{4}\leqslant{x}\leqslant\mathrm{0} \\ $$$$ \\ $$
Answered by Acem last updated on 25/Oct/22
 x∈ [−4, 0] ∪ [4, 8]
$$\:{x}\in\:\left[−\mathrm{4},\:\mathrm{0}\right]\:\cup\:\left[\mathrm{4},\:\mathrm{8}\right] \\ $$

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