(x-1)/[(x+1)^2-4]
=(x+1)/(x+1+2)(x+1-2)
=(x+1)/(x+3)(x-1)
=2(x+1)/2(x+3)(x-1)
(1-x)/(2-4x+2x^2)
=-(x-1)/2(x-1)^2
=-1/2(x-1)
=-(x+3)/2(x+3)(x-1)