Japanese | Can you solve this? | Math Olympiad Problem

[@CharlesChen-el4ot]

5^（x-1)*(25-1)=16
5^(x-1)=2/3
(x-1)log5=log2-log3
x-1=(log2-log3)/log5
x = 1/log5*
(log5+log2-log3)
x=(1-log3)/log5

[@MasterTMathsClass]

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