(x-a-b)/c-1 + (x-c-a)/b-1 + (x-b-c)/a-1 =0
(x-a-b-c)/a +(x-a-b-c)/b +(x-a-b-c)/c =0
(x-a-b-c) (1/a +1/b + 1/c)=0
x-a-b-c=0
x=a+b+c