9. (6 points) If $\overline{\mathrm{ab}} \times 65=\overline{48 \mathrm{ab}}$, then $\overline{\mathrm{ab}}=$
【Solution】Since $\overline{\mathrm{ab}} \times 65=\overline{48 \mathrm{ab}}$, we have $(b+10 a) \times 65=4800+10 a+b$, which means $10 a+b=75$, thus $b=5, a=7$. Therefore, $\overline{a b}=75$.

The answer is: 75.