`a, |x| = 2020`
⇒ \(\left[ \begin{array}{l}x = 2020\\x = -2020\end{array} \right.\)
Vậy `x ∈ { 2020 ; -2020 }`
`b, |x - 1| = 2021`
⇒ \(\left[ \begin{array}{l}x - 1 = 2021\\x - 1 = -2021\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x = 2021 + 1 = 2022\\x = -2021 + 1 = -2020\end{array} \right.\)
Vậy `x ∈ { 2022 ; -2020 }`
`c, (-37) - |7 - x| = 127`
`⇒ |7 - x| = (-37) - 127`
`⇒ |7 - x| = (-37) + (-127)`
`⇒ |7 - x| = -164`
Vì `|7 - x| ≥ 0 ∀x`
nên: `|7 - x|` $\neq$ `-164`
`⇒ x ∈ ∅`
Vậy `x ∈ ∅`
`d, x - 14 < 10`
`⇒ x < 10 + 14`
`⇒ x < 24`
Vậy `x < 24`
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