Given a + B + C = 0, AB + BC + AC = 0, prove a = b = C = 0
If AB + BC + AC = 0, then 2 (AB + BC + AC) = 0
ab+bc+ab+ac+bc+ac=0
(a+c)b+(b+c)a+(a+b)c=0
If a + B + C = 0, then a + B = - C, a + C = - B, B + C = - A
-b^2-a^2-c^2=0
That is, a ^ 2 + B ^ 2 + C ^ 2 = 0
a=b=c=0
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