Interesting exponential equation | Step by step solution

[@CraigHolm]

Ok, solved by a simple observation.
But how would one go about formally deriving the solution?

[@ChidexMath2-w4h]

The right hand side should be focused on

[@pepeluchoamor5069]

Una manera nada elegante de demostrar la igualdad

[@ChidexMath2-w4h]

Can you write in English?