Question

Determinati nr natural N pentru care 2N+2 este divizor al lui 20

Answer 1

2n+2|20=>2n+2∈D₂₀
D₂₀={1;2;4;5;10;20}

Luam fiecare varianta pe rand:
1) 2n+2=1=>imposibil in multimea numerelor naturale
2) 2n+2=2=>2n=0=>n=0
3) 2n+2=4=>2n=2=>n=1
4) 2n+2=5=>imposibil in multimea numerelor naturale
5) 2n+2=10=>2n=8=>n=4
6) 2n+2=20=>2n=18=>n=9