(1) -2=loga9
a^(-2)=9
a=±1/3
又a>0
則a=1/3
函數(shù)解析式f(x)=log(1/3)x
（2）圖像這個(gè)不好畫啊.不過(guò)他過(guò)（1,0）點(diǎn)（9,-2）點(diǎn),畫一條圓滑的對(duì)數(shù)曲線就可以了
（3）對(duì)數(shù)函數(shù)a帶入就可以了啊f(1)=log(1/3)1=0f(1/27)=log(1/3)1/27=log(1/3)(1/3)³=3log(1/3)1/3=3f(3/2)=log(1/3)3/2=lg(3/2)/lg(1/3)=(lg3-lg2)/(lg1-lg3)=(lg3-lg2)/(0-lg3)=(lg2-lg3)/lg3=lg2/lg3-1查對(duì)數(shù)表可知lg2=0.3010，lg3=0.4771計(jì)算可得f(3/2)=-0.369