#ln color(red)(e)#
#color(white)("XXX")=log_color(blue)(e) color(red)(e)#
Remembering that
#color(white)("XXX")log_color(blue)(b) color(red)(a)=c#
means
#color(white)("XXX")color(blue)(b)^c=color(red)(a)#
Therefore
#color(white)("XXX")log_color(blue)(e)color(red)(e)=c#
means
#color(white)("XXX")color(blue)(e)^c=color(red)(e)#
That is
#color(white)("XXX")color(green)(ln_e)=log_e e (= c) = color(green)(1)#
Therefore
#color(white)("XXX")4color(green)(ln_e) + color(green)(ln_e)#
#color(white)("XXX")=4(color(green)(1))+ (color(green)(1))#
#color(white)("XXX")=5#