（lg根号27+lg8-3lg根号10）/lg1.2
= [lg3^(3/2) + lg2^3 - 3lg10^(1/2)] / lg(6/5)
= (3/2 lg3 + 3lg2 - 3/2) / (lg6 - g5)
= [(3/2 lg3 + 3/2 lg2) + (3/2 lg2 - 3/2)] / (lg6 - lg5)
= [3/2 lg6 + 3/2 lg(1/5)] / (lg6 - lg5)
= 3/2 [ lg6 - lg5] / (lg6 - lg5)
= 3/2