Log5 7 x log121 25 x log7 11=

Question

Log5 7 x log121 25 x log7 11=

Answer 1

log 121   25 = log (11)^2   (5)^2  =   log 11  5

log 5  7 = log 11  7 / log11  5 
Имеем:
log11  7/log11  5 * log 11  5  *  1/log11  7  = 1.