Hello, achacy!

I have a somewhat intricate solution.

. . Maybe someone can do better . . .

.[1]

I converted the terms to the same base.

. . Take logs: .

. .

. . Hence: . .[2]

From the Base-Change Formula: . .[3]

Substitute [2] and [3] into [1]: .

We have: .

Let

Muliply by . . . assuming

Multiply by 2: .

There are two cases:

. .

. .

Then we have: .

Multiply by

Therefore: .