Taking away from the variables' exponents has nothing to do with whether 2 has an exponent or not. You only subtract from a variable's exponent when you are dividing by that same variable.

For example, (x^4)/(x^2).... you are dividing x to a power by x to a power, and so, you subtract the exponents, getting x^2.

Sometimes it's easier to visualize with numbers. Here's the same problem, merely substituting 2 for x: (2^4)/(2^2) = 16/4 = 4 = 2^2.

The point being you only subtract exponents when the base is the same. Since two is just a constant, it only affects the constant(s) in the denominator. I'm assuming that this is a homework problem so I don't really want to just come out and give you an answer, but I hope this helps.

36x^5y^2