log_{3}(54)+log_{3}(12)-3log_{3}(2)
=log_{3}(3^2*7)+log_{3}(2^2*3)-3log_{3}(2)
= 2 + log_{3}(7) + 2*log_{3}(2) + 1 -3log_{3}(2)
= 3 + log_{3}(7) - log_{3}(2)