There's nothing there to solve. But you can simplify the expression.
-- The difference of two logs is the log of the quotient.
log₆(25) - log₆(5)
= log₆(25/5) = log₆(5) .
That may be all you can do with it. If they want you to go ahead and actually find the value of log₆(5) ... I don't remember how to do that. If it was log₁₀(5) or ln(5) , those would be easy, because they're right on your calculator. But the log to the base of (anything else other than 10 or 'e') takes an additional step, which I don't remember.