How do I solve/simplify this:

((2a^-2 b^4) / (4a^3 b^-2))^-2

Do I do the ^-2 to everything inside first? Or what steps do I do first?

And how do I factor this:

x^2-7x+12

I don't remember completely as I haven't done it in years, but it has to add up to -7 and multiply together to 12? Or something along those lines...

Any help would be great, thanks.