Question

Determinati multimea:

A = { x apartine Z / |x| < 5, x+3 supra 7 apartine Z}

Answer 1

A= {x∈Z| |x|<5, x+3/7∈Z}
x+3/7∈Z⇒x+3∈D7
                x+3∈{-7,-1,1,7}
            S1 :x∈{-10,-4,-2,4}
|x|<5
-5<x<5
x∈Z⇒S2 :x∈{-4,-3,-2,-1,0,1,2,3,4}
A= S1 ∩ S2
A={-4,-2,4}