in order to solve this problem you have to make your bases the same (similar to what you do with fractions).
instead of having 2^500 & 5^200, why not have 5^z & 5^200, or better yet, 2^500 & 2^w.
But the question is how do you do that? The answer is simple. Express the value of 5 as an exponential expression with a base of two. In other words:
5=2^x, where x is the exponent we need to solve for. Take the logarithm base 2 of BOTH SIDES OF THE EQUATION, and you get this:
log2(5)= x, which means x=2.32...(this number is an approximation)
So now you have 2^2.32= 5, which you can use in the problem above.
5^200= (2^2.32)^200= 2^(2.32*200)= 2^464
And now you can see which one is greater