✔ 最佳答案
3^a=5 log(3^a)=log5 alog3=log5 a=log5/log3 5^b=7 log(5^a)=log7 alog5=log7 a=log7/log5 7^a=9 log(7^a)=log9 alog7=log9 a=log9/log7 abc=(log5/log3)(log7/log5)(log9/log7) =log9/log3 =log(3²)/log3 =2log3/log3 =2
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