若lga,lgb,lgc与lga-lg(2b),lg(2b)-lg(3c),lg(3c)-lga都成等差数列,则正实数a:b:c等于多少

由条件2可得:2lg(2b)-2lg(3c)=lga-lg(2b)+lg(3c)-lga2lg(2b/3c)=lg(3c/2b)(2b/3c)²=3c/2b8b³＝27c³2b＝3cb:c=3:2由条件1可得：2lgb=lga+lgcb²＝ac把b=3c/2代入,得9c²／4＝ac9c＝4aa:c=9:4...