(a+b+c)²=a²+b²+c²+2ab+2ac+2bc
a²+b²+c²=(a+b+c)²
a²+b²+c²=a²+b²+c²+2ab+2ac+2bc
2ab+2ac+2bc=0
ab+bc+ac =0
ab/abc +bc/abc +ac/abc =0
1/c +1/a + 1/b =0
(a+b+c)²=a²+b²+c²+2ab+2ac+2bc
a²+b²+c²=(a+b+c)²
a²+b²+c²=a²+b²+c²+2ab+2ac+2bc
2ab+2ac+2bc=0
ab+bc+ac =0
ab/abc +bc/abc +ac/abc =0
1/c +1/a + 1/b =0