Given a & # 178; + B & # 178; + C & # 178; = AB + AC + BC, judge the relationship between a, B and C

Given a & # 178; + B & # 178; + C & # 178; = AB + AC + BC, judge the relationship between a, B and C

A & # 178; + B & # 178; + C & # 178; = AB + AC + BCA & # 178; + B & # 178; + C & # 178; - AB AC BC = 01 / 2 (2a & # 178; + 2B & # 178; + 2C & # 178; - 2ab-2ac-2bc) = 0 (a-b) & # 178; + (B-C) & # 178; + (C-A) & # 178; = 0, so a = b = C