\[\begin{array}{l}
A = \frac{{2m + 9}}{{14m + 62}}\\
Gia\,\,su\,\,\,2m + 9\,\,\,va\,\,\,14m + 62\,\,\,co\,\,\,\,uoc\,\,chung\,\,\,la\,\,d\\
\Rightarrow 2m + 9\,\,\,\, \vdots \,\,\,d \Rightarrow 7\left( {2m + 9} \right)\,\,\, \vdots \,\,\,d \Leftrightarrow 14m + 63\,\,\, \vdots \,\,\,\,d\\
\,\,\,\,\,\,\,14m + 62\,\,\, \vdots \,\,d\\
\Rightarrow \left( {14m + 63 - 14m - 62} \right)\,\,\, \vdots \,\,\,d\\
\Leftrightarrow 1\,\, \vdots \,\,d\\
\Rightarrow d = 1\\
\Rightarrow 2m + 9\,\,\,va\,\,\,\,14m + 62\,\,\,co\,\,uoc\,\,chung\,\,la\,\,1\\
\Rightarrow A\,\,\,la\,\,phan\,\,so\,\,toi\,\,gian.
\end{array}\]
