Marinada '21

[lang=hr] Koji je zbroj svih rješenja jednadžbe \[ 2 \log_x 3 + \log_{3x} 3 + 3\log_{9x}3=0?\] [/lang] [lang=en] What is the sum of all the solutions of the equation \[ 2 \log_x 3 + \log_{3x} 3 + 3\log_{9x}3=0?\] [/lang]