1、(1) 6a²/12ab, 4b²/12ab,3c/12ab;
(2)9y/6x²y²,10x/6x²y².
2、(1)1/x+1
=(x+1)(x-1)/(x+1)²(x-1),x-1/x²+2x+1
=x-1/(x+1)²
=(x-1)²/(x+1)²(x-1),1/x-1
=(x+1)²/(x+1)²(x-1)
(2)1/x-1
=x(x+1)/x(x+1)(x-1),1/x²-1
=1/(x+1)(x-1)
=x/x(x+1)(x-1),1/x²+x
=1/x(x+1)
=x-1/x(x+1)(x-1)