a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)+3=0
a/b+ac+b/a+b/c+c/a+c/b+3=0
(b+c)/a+(a+c)/b+(a+b)/c+1+1+1=0
(b+c)/a+(a+c)/b+(a+b)/c+a/a+b/b+c/c=0
(a+b+c)/a+(a+b+c)/b+(a+b+c)/c=0
因为a+b+c=0
所以(a+b+c)/a+(a+b+c)/b+(a+b+c)/c=0
所以
a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)+3=0
a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)+3=0
a/b+ac+b/a+b/c+c/a+c/b+3=0
(b+c)/a+(a+c)/b+(a+b)/c+1+1+1=0
(b+c)/a+(a+c)/b+(a+b)/c+a/a+b/b+c/c=0
(a+b+c)/a+(a+b+c)/b+(a+b+c)/c=0
因为a+b+c=0
所以(a+b+c)/a+(a+b+c)/b+(a+b+c)/c=0
所以
a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)+3=0