Question

Va rog..puteti sami rezolvati aceasta fracie?
18
______ apartine N
2x+1

Answer 1

18/2x+1∈N⇒2x-1∈d18=[1,2,3,6,9];
⇒2x-numar par;
⇒1-numar impar;
⇒numar par-numar impar=numar impar;
⇒2x-1=[1,3,9];
⇒2x=2⇒x=1;
⇒2x=4⇒x=2;
⇒2x=10⇒x=5;
⇒x=[1,2,5]∈N;