Question

A={x|x ∈ Z, |x|<7}, B={x|x∈ Z, |x|>2}
AuB, A u intors invers B, A\B, B\A

Answer 1

|x|<7⇔-7<x<7⇔x∈{-6,-5,-4,...,4,5,6,}=A
|x|>2⇔x>2 sau x<-2⇔x∈{3,4,5,6,...}u{...,-6,-5,-4,-3}=B
AuB=(-∞,+∞)intersectat cu Z
A intersectat cu B={3,4,5,6}u{-6,-5,-4,-3}
A\B={-2,-1,0,1,2}
B\A={...,-10,-9,-8,-7}u{7,8,9,10,...}