x=12c+3 ⇒x-3=12c
x=15c+3⇒ x-3=15c
x=27c+3⇒ x-3=27c
(x-3)∈M[12,15,27]
[12,15,27]=3³·5·2²=540
M540={540, 1080, 1620, 2160........}
x-3=540
x=540+3
x=543
540:12=45 rest 3
543:15=36 rest 3
543:27=20 rest 3
deci nr.cel mai mic care indeplineste cond.este nr.543