Question

(a-b)*(a-c)分之2a-b-c加上（b-c）*(b-a)分之2b-c-a加上(c-b)*(c-a)分之2c-a-

Answer 1

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-b)+1/(b-a)]+[1/(b-c)+1/(b-c)]=0+0+0=0