已知loga x=2,logb x=1,logc x=4,则logx (abc)=?

问题描述:

已知loga x=2,logb x=1,logc x=4,则logx (abc)=?

logx (abc)= logx a+logx b +logx c
= 1/(loga x) + 1/(logb x)+1/(logc x)
= 1/2 + 1/1 + 1/4
= 7/4