[tex]\sf{\frac{\overline{ab}}{\overline{ba}}= \frac{9}{2}} \\
9*\overline{ba}=2*\overline{ab} \\
9(10b+a)=2(10a+b) \\
90b+9a=20a+2b \\
90b-2b=20a-9a \\
88b=11a \\
a=8b \\
Daca~a=1 \longrightarrow b=8 \\
Daca~a=2 \longrightarrow b>9 \\ \\
\boxed{\sf{Numarul:18}}[/tex]