Question

Sa se determine elementele multimii: A={n apartine |N | 12n+15 supra n+1 apartine |N}

Answer 1

A={n apartine |N | 12n+15 supra n+1 apartine |N}
n+1 I 12n+15
n+1 I 12n+12+3
n+1 I 12(n+1)+3
n+1 I 3
n+1=1   n=0
n+1=3   n=2
A={0,2}