1.(x+1)(x-1)/(x-1)(x+1)^2,(x-1)^2/(x+1)^2(x-1),(x+1)^2/(x-1)(x+1)^2；1) 6(a+2)/3(a+1)^2(a+2),-1/3(a+2)(a+1)^2 2) 2b^2/6a^2c^2b,-3ac^3/6a^2bc^2,30a^2c^3b^4 / 6a^2bc^2,3) (x+3)/x(x-3)(x+3),2x/(x+3)(x-3)...