若3的x次方=4,3的y次方=6求9的2x-y+27的x-y的值

如题所述

3^x = 4
x= log4/log3

3^y = 6
y=log6/log3

2x-y+27
= 2(log4/log3) - log6/log3 + 27
= (log16-log6)/log3 + 27
= log(8/3)/log3 + 27
= log8/log3 -1 +27
= 3log2/log3 +26
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第1个回答  2010-11-14
原式=3的4x-2y + 3的3x-3y
=3的4x/3的2y +3的3x/3的3y
=4的4次方/6的平方+4的3次方/6的3次方
=
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