(lg根号8 + lg27 - lg根号1000)/lg1.8
=(3/2 lg2+3 lg3-3/2 lg10)/lg(9/5)
=3(-1/2 lg5+lg3)/(2lg3-lg5)
=3/2*(2lg3-lg5)/(2lg3-lg5)
=3/2=1.5