$log_27 5$ = $\frac{1}{3}$ $log_3 5 $ =a $\Rightarrow$ $log_3 5$ =3a$log_8 7$ =$\frac{1}{3}$ $log_2 7$ =b $\Rightarrow$ $log_2 7$ = 3b$log_2 3$=c$log_6 35$ = $\frac{log_2 35}{log_2 6}$=$\frac{log_2 5+log_2 7}{log_2 2+log_2 3}$= $\frac{\frac{log_3 5}{log_3 2}+log_2 7}{1+log_2 3}$=$\frac{3ac+3b}{1+c}$
log27⁡5=a" role="presentation" style="font-size: 13.696px; word-spacing: 0px; position: relative;">log27 $log
-27 5$ =
$\frac{1}{3}$$log_3 5=a suy ra $log_3 5$ =3alog27⁡5=a" role="presentation" style="font-size: 13.696px; word-spacing: 0px; position: relative;">log27 = $\frac{1}{3}$ $log_3 5 $ =a $\Rightarrow$ $log_3 5$ =3a
log27 của 5 =$\frac{1}{3}$$log_3 5$ =a suy ra $log_3 5$ = 3a $log_8 7$ =$\frac{1}{3}$ $log_2 7$ =b $\Rightarrow$ $log_2 7$ = 3b$log_2 3$=c$log_6 35$ = $\frac{log_2 35}{log_2 6}$=$\frac{log_2 5+log_2 7}{log_2 2+log_2 3}$= $\frac{\frac{log_3 5}{log_3 2}+log_2 7}{1+log_2 3}$=$\frac{3ac+3b}{1+c}$