ok, under the assumption that the problem is
\(25^x = 5^{x-2}\)
as opposed to
\(25^x = 5^x-2\)
\(25^x = 5^{x-2}\)
looking the the left side
25 = 5^2 so the left side can be written as
\((5^2)^x = 5^{x-2}\)
now, if you remember exponent rules, a power to a power, you just multiply them together
so it would be equal to this equation
\(5^{2x} = 5^{x-2}\)
now, since they share the same base (5)
you can jsut compare the exponents
2x= x-2
and then solve for x
trying to solve
\(25^x = 5^x-2\)
requires the use of log i believe
