若3a（3的a次方）=2 则 2log3 6 - log3 8=

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已知log3 2=a
2log3 6-log3 8=log3 （6^2/8)=log3 (9/2)=log3 9-log3 2=2-a
结论 2-a======以下答案可供参考======
供参考答案1:
3^a=2alg3=lg2
a=lg2/lg3
2log3 6 - log3 8=2lg2*3/lg3-lg8/lg3
=2(lg2+lg3)/lg3-3lg2/lg3
=2lg2/lg3+2-3lg2/lg3
=-lg2/lg3+2
=-a+2供参考答案2:
2log3 6 - log3 8=log3 [(6^2)/8]=log3 9/2=log3 9-log3 2=2-log3 2=2-a
(3^a=2 , a=log3 2)