3n + 3 + 3n + 1 + 2n + 3 + 2n + 2
= 3n.33 + 3n.3 + 2n.23 + 2n.22
= 3n.(27 + 3) + 2n.(8 + 4)
= 3n.30 + 2n.12
= 3n.5.6 + 2n.2.6
= 6.(3n.5 + 2n.2) \(⋮\) 6
3n+3+3n+1+2n+3+2n+2
=3n+1.(32+1)+2n+2.(2+1)
=3n=1.2.5+2n+1.3
=3.2.3n.5+2.3.2n+1
=3.2.(3n.5+2n+1) chia hết cho 6