1. Simplify the expression

(2a^-2-2b^-2)/(4a^-1+4b^-1)

I know it goes to this

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

I eventually get it down to b-a/2ab

But I guess that's incorrect? I think it has to do with how I'm making the denominators equal.

2. add/subtract\

(4x/x-1)+(4/1-x^2)-(2/x+1)

don't know how to find the lcd?

is the lcd (1+x)(1-x)(x-1)?

thanks for help in advance.