Question:
Solve for x, the inequalities in |x – 1| ≤ 5, |x| ≥ 2
Solution:
|x – 1|≤ 5
There are two cases,
1:-
x – 1 ≤ 5
Adding 1 to LHS and RHS
⇒ x ≤ 6
2:-
⇒ -(x – 1) ≤ 5
⇒ -x + 1 ≤ 5
Subtracting 1 from LHS and RHS,
⇒ -x ≤ 4
⇒ x ≥ -4
From cases 1 and 2, we have
⇒ -4 ≤ x ≤ 6 …[i]
Also,
|x| ≥ 2
⇒ x ≥ 2 and
⇒ -x ≥ 2
⇒ x ≤ -2
⇒ x ∈ (∞, -2] ∪ [2, ∞) …[ii]
Combining equation [i] and [ii], we get
x ∈ [-4, -2] ∪ [2, 6]