Формулы: loga b/loga c= logc b ----> log2 6 / log2 9=log9 6
loga b=1/logb a ----->log9 6 = 1/log6 9
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log2 6 * log6 9 / log2 9 = (log2 6 / log2 9)*log6 9=
=log9 6 * log6 9=log6 9 / log6 9 =1
ответ 1