x/(6ab^2)=3xac/(18a^2b^2c)y/(9a^2bc)=2by/(18a^2b^2c)(a-1)/(a^2+2a+1)=(a-1)(a^2-1)/[(a+1)^2(a^2-1)]6/(a^2-1)=6(a+1)^2/[(a+1)^2(a^2-1)]
