用换底公式log(A)M=log(b)M/log(b)A (b>0且b≠1）a=log(6)π/log(6)3 >1 b=log(6)6/log(6)7 则0c=log(6)0.8/log(6)2=(log(6)5-2log(6)2)/log(6)2=log(6)5-2<0则a>b>c
