3 = lg(1000)
lg(1000) - lg(x-27) = lg(1000/(x - 27))
lg(3x -11) = lg(1000/(x - 27))
3x - 11 = 1000/(x -27)
(3x - 11)*(x -27) - 1000 = 0
3x^2-92x-703 = 0
x = 37, x = -19\3
ОДЗ:
x - 27 > 0
x - 27 != 1
3x - 11 >0
x > 27,
x != 28
x > 11\3
x > 27 и x != 28
C учетом ОДЗ ответ: x = 37;