[tex]3ab+a=2001 \Leftrightarrow a(3b+1)=2001. \\ \\ Factorii~primi~ai~lui~2001~sunt~3,~23~si~29. \\ \\ Distingem~urmatoarele~cazuri: \\ \\ i)~3b+1=1 \Rightarrow b=0 \Rightarrow a=2001. \\ \\ ii)~3b+1=667 \Rightarrow 3b=666 \Rightarrow b=222 \Rightarrow a=3. \\ \\ Solutie:~(a,b) \in \{ (2001,0);(3,667)\}.[/tex]
