HELP MEEEE !!!! Bờ Li

$\begin{array}{l}
{\log _6}63 = {\log _6}\left( {9.7} \right) = {\log _6}9 + {\log _6}7\\
 = {\log _6}{3^2} + {\log _6}7 = 2{\log _6}3 + \dfrac{1}{{{{\log }_7}6}}\\
 = \dfrac{2}{{{{\log }_3}6}} + \dfrac{1}{{{{\log }_7}6}} = \dfrac{2}{{{{\log }_3}3 + {{\log }_3}2}} + \dfrac{1}{{{{\log }_7}2 + {{\log }_7}3}}\\
 = \dfrac{2}{{1 + \dfrac{1}{a}}} + \dfrac{1}{{\dfrac{1}{{{{\log }_2}7}} + \dfrac{1}{b}}}\\
 = \dfrac{2}{{1 + \dfrac{1}{a}}} + \dfrac{1}{{\dfrac{1}{{{{\log }_2}3.{{\log }_3}7}} + \dfrac{1}{b}}} = \dfrac{2}{{1 + \dfrac{1}{a}}} + \dfrac{1}{{\dfrac{1}{{ab}} + \dfrac{1}{b}}}\\
 = \dfrac{2}{{\dfrac{{a + 1}}{a}}} + \dfrac{1}{{\dfrac{{1 + a}}{{ab}}}}\\
 = \dfrac{{2a}}{{a + 1}} + \dfrac{{ab}}{{a + 1}} = \dfrac{{a\left( {2 + b} \right)}}{{a + 1}}\\
 \Rightarrow m = 2,n = 1\\
 \Rightarrow 2m + 3n = 7
\end{array}$