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Here is the solution to `5^x = 4`
`5^x = 4`
take the logarithm of both the sides and use the logarithmic property `log(a^b) = b*log a`
`log(5^x) = log 4`
=> `x*log 5 = log 4`
=> `x = (log 4)/(log 5)`
The solution of `5^x = 4` is `x = (log 4)/(log 5)`