Question

Fie multimile A= { x apartine Z \ | 2x - 1 | < sau egal 3 } ....B= { x aprtine lui N* \ -1 < sau egal 2 -x < sau egal 5 }

Answer 1

 A= {x∈Z / |2x-1| ≤ 3}
|2x-1| ≤ 3 ⇒ -3 ≤ 2x-1 ≤ 3 ⇔ -2 ≤ 2x ≤ 4 ⇔ -1 ≤ x ≤ 2 ⇒ x∈ {-1,0,1,2}

B= { x∈ N* / -1 ≤ 2-x ≤ 5 }
-1 ≤ 2-x ≤ 5 ⇔ -3 ≤ -x ≤ 3 ⇔ 3 ≥ x ≥ -3 ⇒ x ∈ {1,2,3}