1) Используем равенство log2(x) = log3(x)/log3(2):
log3(x) * log3(x)/log3(2) = 4log3(2)
(log3(x))^2 = (2log3(2))^2
(log3(x))^2 = (log3(4))^2
log3(x) = log3(4) или log3(x) = -log3(4)
x = 4 или x = 1/4
2) log5(x) = log3(x)/log3(5) = log3(x) * log5(3)
log3(x) * log3(x) * log5(3) = 9log5(3)
(log3(x))^2 = 9
log3(x) = 3 или log3(x) = -3
x = 3^3 или x = 3^(-3)
x = 27 или x = 1/27