To solve for x in the equation 25^x - 12 = 1/5, we can first rewrite the fraction as a decimal:

25^x - 12 = 0.2

Next, add 12 to both sides of the equation:

25^x = 12.2

Now, we need to take the natural logarithm of both sides to solve for x:

ln(25^x) = ln(12.2)

x * ln(25) = ln(12.2)

x = ln(12.2) / ln(25)

Using a calculator, we can find the approximate value of x to be 0.336.

Therefore, the solution to the equation 25^x - 12 = 1/5 is x = 0.336.