log(a) b = 1/log(b) a
log(x) 3 + log(3) x = 2
одз x>0 x≠1
log(x) 3 = t
t + 1/t = 2
t² - 2t + 1 = 0
(t-1)² = 0
t = 1
log(x) 3 = 1
x = 3
