Đặt $a=\log_{m} x =>x=m^a$Pt $\Leftrightarrow 8 \log _{m} x.\frac{\log_m x}{\log_m n}-7\log _mx-6\frac{\log_m x}{\log_m n}-2017=0$
$\Leftrightarrow 8a^2\log_n m-7a-6a\log _nm-2017=0$
Theo Vi-et có
$\log _mx1+\log_m x2=\log_m x1x2=\log _mP=\frac{7+6\log_n m}{8\log _nm}=\frac{7}{8}\log _mn+\frac{6}{8}$
$\Rightarrow P=m^{\frac{7}{8}\log_m n+\frac{6}{8}}=m^{\frac{6}{8}}.n^{\frac{7}{8}}=\sqrt[8]{m^6.n^7}$
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