Question

6、3^a=2，則log₃8-2log₃6=

a-2

．

Answer 1

分析：由對(duì)數(shù)式和指數(shù)式的轉(zhuǎn)化，由3^a=2表示出a，再由對(duì)數(shù)的運(yùn)算法則對(duì)log₃8-2log₃6進(jìn)行化簡(jiǎn)即可．

解答：解：由3^a=2得a=lg₃2，所以log₃8-2log₃6=log₃2³-2log₃2×3=3a-2a-2=a-2
故答案為：a-2

點(diǎn)評(píng)：本題考查對(duì)數(shù)式和指數(shù)式的轉(zhuǎn)化及對(duì)數(shù)的運(yùn)算法則，考查運(yùn)算能力．