Question

n apartine N, n=? (2n +1 ) se divide cu ( 3n +9 )

Answer 1

3n+9/3n+9
3n+9?2n+1 rezulta ca 3n+9 divide orice combinatie din cele doua
3n+9/2(3n+9)-3(2n+1)
3n=9/6n+18-6n-3
3n+9/15
3n+9(-{0,1,3,5,15) scadem 9
3n(-{6}
n=2