This is a logarithmic formula: log(a)b=[log(c)b]/[log(c)a)]

Proved as follows:

Let log(a)b=n, then b = a n n, then log (c) b = log (c) an n = nlog (c) a.

So the formula on the left =n,

And the formula on the right = nlog (c) a/[log (c) a)] = n.

Therefore, the bottom-changing formula is established.

So: log (14) 7 = [㏒ (35) 7]/[㏒ (35)14]

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