2a-b-c/(a-b)(a-c)+2b-c-a/(b-c)(b-a)+2c-a-b/(c-a)(c-b)=[(a-b)+(a-c)]/(a-b)(a-c)+[(b-c)+(b-a)]/(b-c)(b-a)+[(c-a)+(c-b)]/(c-a)(c-b)=1/(a-c)+1/(a-b)+1/(b-a)+1/(b-c)+1/(c-b)+1/(c-a)=[1/(a-c)+1/(c-a)]+[1/(a...