Question

log(3)7 × log(4)81 × log(7)2

Answer 1

log3 (7) * log 4 (81) * log7(2) 
= log 4 (7) * log 3 (81) * log7 (2) = 
= log 7 (7) * log3 (81) * log4 (2) = 
= 1 * 4 * 1/2 = 2 

Применил два раза 14 свойство