Explanation:
I'm going to assume you mean
which can be rewritten as
since if you start with
since when you do (10^x)^c you're just multiplying the exponent which is represented by the x but is equal to the log you just multiply the log which is why you can bring it in front.
You can then approximate the value of log(5) using a calculator and multiply by 125 to get around 87.371