Math problem, Logarithm. Is 2(Log2x-Logy) becomes 2Log4x-2Log2y or 2Log2x-2Logy?

It's the second one: 2log2x-2logy. When expanding brackets, treat logs the same way as exponents (i.e. x², y²) and you won't go far wrong. Although there are clever things you can do with logs that you can't do with exponents.

i.e. 2logx = logx²

The log of 25 is exactly twice the log of 5.