-3 a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)=a/b+a/c+b/a+b/c+c/a+c/b=(a+c)/b+(a+b)/c+(b+c)/a因为 abc不等于0,a+b+c=0所以 a+c=-ba+b=-cb+c=-a所以(a+c)/b+(a+b)/c+(b+c)/a=-1+（-1）+(-1)=-3即a(1/b+1/c)+b(1/a+1/c...