Răspuns :

-3<2x+1<7 (scadem 1)
-4<2x<6 (impartim la 2)
-2<x<3, rezulta ca x apartine (-2, 3) Bafta !
2x+1=4/-1 2x=3/:2 -nu da nr natural 2x+1=5/-1 2x=4/:2 X=2-da nr natural deci e bine 2x+1=6/-1 2x=5-nu da nr natural