log₃ 72 -log₃ (16/27) +log₃ 18= log₃ 72 - log₃ 16 - log₃ 27 + log₃ 18=log₃(72/27)-log₃(16*18)=log₃(8/3)-log₃16+log₃18=log₃8-log₃3-log₃16+log₃18=log₃(8/16)-log₃3+log₃18=log₃(1/2)+log18-1=log₃1-log₃2+log₃18-1=0-log₃2+log₃18-1=log₃18-log₃2-1=log₃(18/2)-1=log₃9-1=2-1=1